I have the exact same problem! DS is 13 mos, 30lbs 31in. So far DS can only wear elastic waist pants. Jeans are totally out, he needs a 3 in every brand I've tried and they are way too long. I can roll them up but he hates to wear them.
I've had good luck with BabyGap knit pants
http://www.gap.com/browse/product.do...&pid=763422022
They only have black on the website but I got gray, navy and brown in the store. DS can wear a 2T.
He can also wear some styles of Carters pants in 24mos. The 24mos seem to be shorter than a 2T even thought they are really the same size.
Stay away from Old Navy and Childrens Place. Pants seem narrow in the waist even for a 3T.
I haven't tried Hanna just because DS seems to grow out of clothes so fast I haven't wanted to invest that much. I haven't liked any of the Gymboree lines lately so haven't tried those either. Gymboree does tend to run larger than other brands. So your DS might be able to wear a 2T.
No help with the hemming, but I need to learn how to do it also!
-Krystal
DD 2/04
DS 10/5/10