I too was fascinated by that thread. Unfortunately I had JUST put a new battery in my wife's Toyota Matrix.
Maxwell Technologies sells a group 31 ultra-capacitor for heavy duty trucks. Normally, HD trucks have four 12V lead acid batteries (wired in parallel for 12 volts and 3000-3600 CCA), but apparently in the prairies in the ultra-cold weather they are trying three batteries with one capacitor unit with massive success.
Maxwell Technologies Engine Start Module: for saving money, it's the fleet service manager's choice
Even if the batteries get discharged down to 9 volts, a single capacitor unit with still start the truck.
I would love to build a cheap/tiny lithium/cap unit to try in my motorcycle, although nothing is wrong with the battery it has in it.