Ok, this will probably seem crazy to people but that is ok
Just let me know if you have any suggestions and what they are.
This combination starts at level 11 (first level taken then, this is the earliest possible I believe) and ends at 20. I split it up into two prestige classes because I wanted those who stuck it out to the higher parts to get better skill points and it makes the saves come out exactly between good and bad.
The jack of all trades is to make the character good at a great number of things but not as good as anyone else, just a wider breadth. If there is a more elegant way to restrict skills than I have done let me know
Basically the character has to have a ton of different levels, has to pick up nothing but a feat that is interesting, but not terribly useful, and will never get very high class abilities for any particular class. Hope it goes well!
Feat: Jack of All Trades (general)
Benefit: Once per day the character with this feat may add +1 to a single skill check (no matter how long one use takes). If used on a skill with which the character has no ranks the bonus is +2 instead. If taken multiple times they may be used in any combination of seperately or together.
Jack of All Trades, Master of None
Hit Die: d4.
Requirements
To qualify a character must fulfill all the following criteria.
Feats: Jack of All Trades x4. (plus 1 if having an extra bonus feat from race that can be used for it)
Class: At least 2 levels in 5 different non-prestige classes.
Class Skills
All skills of previous classes are class skills.
Skill Points at Each Level: 4 + Int modifier.
Table: Jack of All Trades
Level BAB Fort Ref Will Special
1st +0 +0 +0 +0 JOAT
2nd +1 +0 +0 +0 JOAT
3rd +1 +1 +1 +1 JOAT
4th +2 +1 +1 +1 JOAT
5th +2 +1 +1 +1 JOAT
Class Features
All of the following are Class Features of the Jack of All Trades, Master of None prestige class.
Weapon and Armor Proficiency: An No new proficiencies are gained.
Skill Ranks: The max ranks a character can have is reduced by 2 (ie level +1 for class skills).
JOAT: Each level in this class the character gains class abilities as though one level higher in 5 different classes (chosen when the class is first taken).
Jack of All Trades
Hit Die: d12.
Requirements
To qualify a character must fulfill all the following criteria.
Feats: Jack of All Trades x6. (plus 1 if having an extra bonus feat from race that can be used for it)
Class: At least 2 levels in 5 different non-prestige classes, and all 5 levels of Jack of All Trades.
Class Skills
All skills of previous classes are class skills.
Skill Points at Each Level: 6 + Int modifier.
Table: Jack of All Trades
Level BAB Fort Ref Will Special
1st +1 +2 +2 +2 JOAT
2nd +2 +3 +3 +3 JOAT
3rd +3 +3 +3 +3 JOAT
4th +4 +4 +4 +4 JOAT
5th +5 +4 +4 +4 JOAT
Class Features
All of the following are Class Features of the Jack of All Trades, Master of None prestige class.
Weapon and Armor Proficiency: An No new proficiencies are gained.
Skill Ranks: The max ranks a character can have is reduced by an additional 2 (ie level -1 for class skills).
JOAT: Each level in this class the character gains class abilities as though one level higher in 5 different classes (chosen when the class is first taken).

This combination starts at level 11 (first level taken then, this is the earliest possible I believe) and ends at 20. I split it up into two prestige classes because I wanted those who stuck it out to the higher parts to get better skill points and it makes the saves come out exactly between good and bad.
The jack of all trades is to make the character good at a great number of things but not as good as anyone else, just a wider breadth. If there is a more elegant way to restrict skills than I have done let me know

Basically the character has to have a ton of different levels, has to pick up nothing but a feat that is interesting, but not terribly useful, and will never get very high class abilities for any particular class. Hope it goes well!
Feat: Jack of All Trades (general)
Benefit: Once per day the character with this feat may add +1 to a single skill check (no matter how long one use takes). If used on a skill with which the character has no ranks the bonus is +2 instead. If taken multiple times they may be used in any combination of seperately or together.
Jack of All Trades, Master of None
Hit Die: d4.
Requirements
To qualify a character must fulfill all the following criteria.
Feats: Jack of All Trades x4. (plus 1 if having an extra bonus feat from race that can be used for it)
Class: At least 2 levels in 5 different non-prestige classes.
Class Skills
All skills of previous classes are class skills.
Skill Points at Each Level: 4 + Int modifier.
Table: Jack of All Trades
Level BAB Fort Ref Will Special
1st +0 +0 +0 +0 JOAT
2nd +1 +0 +0 +0 JOAT
3rd +1 +1 +1 +1 JOAT
4th +2 +1 +1 +1 JOAT
5th +2 +1 +1 +1 JOAT
Class Features
All of the following are Class Features of the Jack of All Trades, Master of None prestige class.
Weapon and Armor Proficiency: An No new proficiencies are gained.
Skill Ranks: The max ranks a character can have is reduced by 2 (ie level +1 for class skills).
JOAT: Each level in this class the character gains class abilities as though one level higher in 5 different classes (chosen when the class is first taken).
Jack of All Trades
Hit Die: d12.
Requirements
To qualify a character must fulfill all the following criteria.
Feats: Jack of All Trades x6. (plus 1 if having an extra bonus feat from race that can be used for it)
Class: At least 2 levels in 5 different non-prestige classes, and all 5 levels of Jack of All Trades.
Class Skills
All skills of previous classes are class skills.
Skill Points at Each Level: 6 + Int modifier.
Table: Jack of All Trades
Level BAB Fort Ref Will Special
1st +1 +2 +2 +2 JOAT
2nd +2 +3 +3 +3 JOAT
3rd +3 +3 +3 +3 JOAT
4th +4 +4 +4 +4 JOAT
5th +5 +4 +4 +4 JOAT
Class Features
All of the following are Class Features of the Jack of All Trades, Master of None prestige class.
Weapon and Armor Proficiency: An No new proficiencies are gained.
Skill Ranks: The max ranks a character can have is reduced by an additional 2 (ie level -1 for class skills).
JOAT: Each level in this class the character gains class abilities as though one level higher in 5 different classes (chosen when the class is first taken).