Not just the size, the 226's frame is aluminum with a stamped-steel slide. The 229 is a stainless steel slide. Also, I don't think the 226 is available in DAK. Keep in mind the longer slide on the 226 gives for better sight picture accuracy i'm told, I don't have research to prove this.
Although the 229 is considered compact it really isn't all that small. It's really nice, my father in law has one and it shoots beautifully but it certainly isn't very small. If you're looking for a 226 but smaller the 229 is great but the 228 aesthetically looks more like the 226 and I think is more alike in every way. Except the small detail of the trigger guard, the 226 and 229 share the same trigger guard, the 228 does not, it's trigger guard doesn't have the hard edge on it. The only problem is that the 228 is not available new right now due to supply to U.S. armed forces. The NP-34 is a popular and very nice copy of the 228 (the odd lemon exists though, like everything in life, some would say).
Tim.