I'd think if I saw someone setup with an 8x10 on the street, they'd be after some sort of architectural image, and I'd really ignore them as a street photographer, especially in comparison to someone with a big piece of L glass on a canon dslr. Nobody can really tell the exact moment you take a photo with a view camera unless you are showing your hand with the cable release. But you won't be able to get high shutter speeds with a typical 8x10 lens.
4x5 with tmax400 film will be surprisingly high quality, and people'd probably still mistake you for someone doing architecture or a glass plate fool. (They'd ask if you can still get film for that)