I'd recommend eBaying yourself a version 1. Or just buy a SG2 @ $retail and re-sell it once you've had your way with it. You'll likely get 80-90% of your money back.
Don't underestimate the benefit you can get from it. If you use it with the honest intention of modifying your technique behind the wheel, it will pay for itself, no question.
it would be cool if you could rent one so you can see where you are driving poorly for fe, then once you have adjusted your driving habits, send it back to the rental place.
Several times we've talked about buying one collectively to loan out to GS members, but nothing has come of that. Maybe we need to dangle the capitalist carrot to get the plan in action: Buy one, then RENT rather than loan it out, as you suggest. Matt, are you reading this? It would be a great benefit to "members in good standing".
I belive the run flat tires that come standard on new cars have a plastic donut, and require special wheels, so when your tire blows, it starts riding on the donut that is around the rim, the rest of them are just stronger side walls, also, are t here any narrow or LRR tires out there that are also run flats? I suspect not.
if you want to save even more weight when you remove your spare, replace the electric air compresser with a small hand pump, they take up less space weigh less, cost less and don't require electrical power.