One of my best friends is also a 28 (only much taller, which actually makes life even harder). I can ask him next time I talk to him (which will probably be soon).
Banana Republic has the male equivalent of a 00 sold only online, so if you go to a store you won't find it. Unfortunately their suiting seems to start at a 29.
http://bananarepublic.gap.com/.....?cid=43620
I know my VSF (very skinny friend) is a big fan of H&M. Their men's clothing is cut a lot like their women's: tiny. He also told me he shops in some Japanese store, because their clothes tend to run quite small, but I don't know what it is or if they would have one near you (it isn't Uniqlo but something else, so I'll ask him about it). Basically, if you have any Euro retailers near by (H&M, Zara, Esprit) off the top of my head, try there. I don't think they're necessarily good suit places, though.
Does Club Monaco sell men's clothing? I know they run small in women's so it might be worth it to look around there.
J Crew has an XS section as well, and they actually have suits, unlike silly BR.
http://www.jcrew.com/AST/Brows...../suits.jsp
I believe Brooks Brothers can make a custom suit, which while pricey, would be pretty killer to have. Sizing and alteration info is here:
http://www.brooksbrothers.com/.....g.tem#size
Wow, I really want to try that digital alteration thingy!
I'm sure people with significant others and husbands will probably have more detailed input.