The GSL says that gunslingers are not D&D. Didn't you get the memo?
Personal tastes aside, a "Split the Tree" power would work for a gunslinger w/ 2 pistols.
Perhaps as the PC went up in power, the multiple shot thing could increase in power. (Though who the heck knows given we seem to know nothing certain about 2 weapon combat in 4E.)

Personal tastes aside, a "Split the Tree" power would work for a gunslinger w/ 2 pistols.
Perhaps as the PC went up in power, the multiple shot thing could increase in power. (Though who the heck knows given we seem to know nothing certain about 2 weapon combat in 4E.)