Matthias Wandel has plans for a bandsaw sawmill. I think his is a 14 inch capacity, which would be plenty for me. I've bought the plans and I have all the parts to get started, but I haven't built yet. Will do it in the spring. Should be be able to easily get the saw, generator, and lumber in the back of even a small pickup.
There are other forums with much bigger versions, up to trailer mount. What size are you going for?