Yeah, I know.
I did get the insulation done and finished the interior pretty nicely, and looked at a few "Shop Hawg" propane heaters but have been that route before - You really need to run the heat to at least 50F all the time so your tools are warm-ish when you handle them. It would also be Über-nice to have radiant heat in the floor slab and THAT's never gonna happen unless I put a grid floor over the slab (I think about that from time to time, too.) All this thinking takes it's toll, though:
You know you are getting old when it takes too much effort to procrastinate.
But then, and more for Alan's benefit, I remember that little sign I used to have on my office wall, a quote from the poet Ogden Nash:
Is To Rot"
There might be hope for me, yet!