WOW. This is a question I should've asked years ago.
Since my sn is tallest1, I think I most qualify to answer this:
I am a 38x38 and I get my short pants (jeans shrink too fast, so I get mostly cargo pants now) (as in baggy & below the knee) from Target's Utility line. Target also has a good supply of tall colored T-shirts. They're inexpensive and they last long. I get my long jeans/cargopants from a place called Demo, a shop full of 'urban' clothes. Since baggy pants are the 'in' thing and they have buy 1 get 1 free sales like every 3 monthes, I have no problem finding long pants there. For long khakis, I custom order from the JCPenny Tall men's or Big and Tall Mens catalog. For tuxedos and formal wear, I get custom fit.
However, the one thing I haven't found are good tall collared shirts (white ones [for work] and casual ones). The tall casual shirts, are long but they always make the sleeves embarrassingly short :|. White collared shirts for our size, as far as I know, don't exist. I RARELY wear them since I look stupid in 'em.
( If you're reading this and theres any other places I haven't mentioned, PLEEEEEASE for the love of tall people, post!! )
Edit: LordMaul and anyone else - post your dimensions too please