I have a pole barn that is about 22'Wx50'L long and skinny isn't great for use of space. I would have much preferred a 32'wx35'L or something along those lines. Mine came with the house so I won't complain too much.
If you get much snow any doors on the sides will be a pain in the ass, Doors on the ends are much nicer (again long and skinny sucks).
If you plan to heat it I would highly recommend in floor heat. It will be much more comfortable then any type of forced air heat. If not in floor heat the hanging radiant tube heaters are pretty nice.
Go with roll up doors. I have big hinged doors and they are not great, don't seal well ect. (the one on the side is terrible when the snow dumps off the roof in front of it). The big sliders are not much better.
The fiberglass panels they use to let light in don't last very long. Mine were about 12 years old and you could easily stick a finger through them. If you decide to use them at least put them on the walls and not the roof.
Consider some type of "bonus truss" with the extra large space in the middle for storage. They won't cost very much more then standard truss's.
Post pictures when it's done