Oh yes, folks have done that too. 1/6 roughly equates to 3 in 20 (a bit closer than it does to 4 in 20). So, for example, you can call a 1/6 ability an 18 or better on a d20. I know some folks have done full charts. I don't have one handy but I'm sure I saw one last week.
The Thief % skills have percentages that aren't all multiples of 5, but it's hardly a big impact to round them off to the nearest 5 and just convert direction to d20 target numbers.
Level 1 B/X Thief has 87% Climb, 10% Find/Remove Traps, 10% Hide in Shadows, 20% Move Silently, 15% Open Locks, 20% Pick Pockets.
D20 equivalent values: 3+ Climb, 19+ Find/Remove, 19+ Hide, 17+ Move Silent, 18+ Open Locks, 17+ Pick Pockets. And the 1-2 Hear Noise can be 13+.
Of course, the side benefit of just switching them all (except Climb) to the Hear Noise chance, for me, is bumping up their odds while I'm at it so they're not so crappy at their jobs.