Perhaps this info will be useful for somebody looking for spare tire solution on F10/F11.
In my case i went with the following setup for my 2011 528i and worked for me. Might not work for some 535 or 550 due to larger brakes.
I couldn't find anything ready to go here in Toronto Canada, and I didn't want to pay for shipping from US otherwise I would probably get a spare setup from this link
http://www.bimmerzone.com/BMW_Performance_Spare_Tire/BIM-SST-F10-KIT.html
As I mentioned you'll need to check brake clearance on your car.
And you can use tire size comparison to check tire radius difference
https://tiresize.com/tyre-size-calculator/
Small variations are acceptable.
I got a used spare rim from BMW E60 model (it has the same bolt pattern as our F10s) and I used 135/90R17 rubber for this spare rim. Original spare rubber for e.60 is 135/80R17 which has a smaller rolling diameter than our F10s.( Based on tire size calculator its around 4.7% smaller). That's why I had to get a different rubber 135/90R17
I also got 15mm spacer and extended wheel bolts to accommodate the 15mm spacer for the spare which was needed to clear brakes on my car. As I mentioned you'll need to check if this setup will work for yours.
Overall cost for me was 50CAD for used E60 spare rim + 10CAD for used 135/90R17 rubber + 80CAD for 15 spacer and bolts. So total cost for me was $140 CAD.
PS I'm using 225/55R17 for winter tires and 245/45R18 for summer tires. Based on tire size calculate the variation between my summer/winter tires vs spare donut is around 0.4% which should be OK for short distance travel with lower speeds.
Some people also suggested to use spare wheel from certain year model X3, however I didn't explore that option