Assuming that one who does wet plate will not be transporting the camera too far from studio or vehicle, size/weight is not a major make-or-break factor.

Seems like a 11x14 studio camera with an 8x10 back would be a fine way to go -- start of with 8x10 then slowly gather the equipment you need to move up to 11x14. Perhaps looking for lenses that might serve both formats.