Sealing & finishing OSB

I recently picked up a very cheap and large trailer. I thought it would be great for a slightly larger and odder than normal teardrop. I would like to keep costs down if I go that route of teardrop, having looked at build methods and materials, I think OSB wouldn't be bad for exterior giving the fact that the stick frame will be thicker than normal, for extra insulation. I know it won't be long before the plywood vs OSB argument gets brought up not interested in that.
It has far less voids than plywood, It is very strong and cheaper long run. My question is what would be the best way to seal it and finish it. I have seen some finished OSB floors, cabinets, that looks very interesting. I wish I could get the wood to look more like old grey barn wood, but I don't think that is a option or all that possible. Maybe with spray paint in a light coating. But after that, how would one go about sealing it or will it not take sealing very well? Would layers of clear varnish, polyurethane or epoxy work? Can I treat the wood as if it was a normal plywood exterior? I am not planning on edge moldings or trim, unless it would be to cover panel edges. I don't like the idea of having a painted surface unless it is the best way to preserve the wood and seal it. Where I am, once in a great while we get small hail, and sleet. This will be outside 24/7. I might cover it during winter. Winter -10F at most, summer 110F at most. Fair amount of rain in Michigan, so I do think moisture will be a issue needed to address along with the other elements. Is there a good way to effectively, protecting the natural look of the wood, sealing it from the elements that will last? Can this also be used over the surface is painted? Thank you in advance, especially if you have done it with lasting results! - Vajra
