Don't know about weisswurst, but any decent Polish deli should have veal weiners. They're called
parówki cielęce, if for some reason you can't find the English name. I know that Dunajec in Hickory Hills has them, and I suspect a place like Celina's in Lemont would have them (although that's just a guess--never been there. Judging by the photos
here, it looks to me like a typical Polish grocery that would have it.)
Celina's Deli & Pantry
814 State St
Lemont, IL 60439
Actually, I just called, and they said they do have veal wieners, so there you go...