I am looking to buy some new suits and am struggling to find ones that
fit.  I'd ideally like online options as I don't have a car, and I
don't want to pay exorbitant designer prices.

My measurements are 33 1/2, 26 1/2, 35; I'm not emaciated, just seems
like suits run larger than normal clothing.  To add to the
complication, I'm 5'7" with a 33" inseam, so petite styles will in no
way cut it!  So I'm looking most-likely for Size 0 or maybe even
0-Tall (having to hem is better than nothing.)

My best options so far seem to be Ann Taylor (and AT Loft) and Banana
Republic.  Would love to know what other options I might have,
however, as even those two merchants don't have an abundant number of
options that are professional looking (can't really wear the white
summer linen suit in the corporate world!)  I've tried on Anne Klein
2s (proportions are great, but are too big), Michael Kors 2
(proportions okay, but too big) and Calvin Klein 2s (proportions
wrong, and big to boot).

Please help!

You might try J. Crew online, if you haven't already. My daughter gets
their catalogues, and it looks like they have been working on
developing a "professional" line of suiting in various kinds of
wools/blends and in neutral colors. Their clothes also seem to run on
the skinnier side. If you haven't seen them, you can check out this
page, bottom third of the page: 
http://www.jcrew.com/catalog/category.jhtml?id=cat103166&navAction=jump.

I will check them out. Thank you!!!!