Copied from TM Model S Forum. NoMorePetrol offered his research to everyone, so I wanted to make sure it was available to TMC users.
Spare tire solution
NoMorePetrol | December 3, 2015
A compact spare (wheel and tire) that fits in the frunk. Rolling diameter, lug pattern, load - all good. $340.
http://www.bimmerzone.com/BMW_Performance_Spare_Tire/BIM-SST-F25-KIT.html
A Tesla sized centering ring for the spare (also shown on the page with the spare). $10.
http://www.bimmerzone.com/BMW_Performance_Spacers/PRT-7465.html
A 1/2 inch drive 21mm thin wall socket. $12.
http://amazon.com/Wilmar-Performance-Tool-W32925-2-Inch/dp/B00H8A57PS/re...
A 1/2 inch drive by 25 inch breaker bar (those lug nuts are on tight) for the socket. $20.
http://amazon.com/gp/product/B00MWVAUT6?psc=1&redirect=true&ref_=oh_aui_...
For a jack - low clearance, heavy load, high quality (it is holding your Model S) - I went with a 2011 Acura MDX jack.
The tire fits nicely in the frunk, as if the frunk was sized just for that purpose. The jack and the rest fit nicely behind the spare in the compartment. There is still quite a bit of room left in the frunk, around and on top of the spare. Put the tire in upside down so you also have the room "inside" the tire.