I would also agree with sig 229; get the factory .357sig barrel for your 229, I think I got mine through top gun supply, but check around for the best price, TGS has my backing in that they always ship to me very quickly.
The 226 is a little longer and heavier, but I think it shoots pretty similarly to the 229. If I had found a 229 as cheap as my 226 and got it first I would have passed on the 226. Other than a slight muzzle and therefore velocity increase the 226 has a slightly longer sight radius maybe a tad more controllable from the slight weight increase. Like you said, the 229 was built for the .357sig or visa versa and the only thing that will give away your barrel change is your sig box (to my knowledge)