Nope. Apple locks the firmware on their systems own *HARD*. <snip!> you'd need some of the hardware-specific files since Snow Leopard doesn't have "public" releases that support things like Sandy Bridge and Thunderbolt.
What are you talking about? The 2011 MBPs and iMacs have Sandy Bridge and Thunderbolt in them. There's lots of support for SB and TB in Snow Leopard still.
BUT... there are new chips like then ew Broadcom Bluetooth 4.0 chip, and like you mention a new Thunderbolt/Intel Controller chip that might cause problems to Snow Leopard.
It's entirely possible that support for that chipset is absolutely missing in Snow Leopard, making back-porting truly impossible.
That's true. But if one could get the right kext's from Lion and get them working in SL, you'd be in business.
So, I'd go with "hard to do", but not "impossible".
Regardless, I dunno why people hate on Lion so much - It's a decent OS, IMHO. There's also always
running SL in a VM if you really want to use it w/o much hacking...