I have a 22-25L backpack with 2 sections that can fit both my Medium format (GW690) and a m43 with the 35-100 with space for some light provisions, film and a 35mm P&S. Yep, carried all of it a few times. Usually for 25-30km rides. For longer ones, even a generic Camelbak type without the water reservoir fitted the m43 tele kit or a nikon F90+Prime rather well.
My (now ex) bike was a 29er MTB but I tend to do cross country gravel roads with not very technical segments. For a shot, I just stop, hang my packpack to the front, take camera out and shoot. Sometimes I just lean the bike a bit and take a bit for the picture. A bit like artillery but has worked well.