Heres the heater I'm looking at: http://heatall.com/furnaces/bryan_furnace.html
Spray foam insulation. Have a crew come in and spray it all. Thats what I'm thinking about doing so I don't have to mess with putting a ceiling in and leave the rafters open for storage. I will still OSB the walls though.Back to insulation...
The interior will be unfinished so no ceilings or anything. How do you insulate the underside of the roof? Is there such a thing as insulation with a sticky side or do you have to put something across the exposed side to keep it from sagging / falling?
Spray foam insulation. Have a crew come in and spray it all. Thats what I'm thinking about doing so I don't have to mess with putting a ceiling in and leave the rafters open for storage. I will still OSB the walls though.
It's a great idea and product but just not enough budget for it.

For sure figure out some kind of cross ventilation be it a rear walk-in door or windows. I had a 30x40 built in dec. they used "bubble wrap" type. It was around 1/2 price of plastic backed type, works just as good too.
I don't know if your gonna do it yourself or have it built but theses guys did mine http://www.maderightbuildings.com/ . I've got about 15k in it slab, insulation,erection and including the dirt.
Just plan to build an outdoor room for your compressor, takes a tiny bit more concrete and a bit more wood and insulation to make it quiet enough to not bother anyone but well worth it. Certainly not a budget buster

John, I can only say one thing about your plans: go bigger.
Trust me on this, I wished I had built mine bigger than the 30 x 50 it is now. Don't spend money twice. Just do it once and be done with it.

