as i understand it, 1155 is the socket which works best.
you might run into problems with the 2011 (e.g., power management and speed step as jester969 mentioned), as there are no 2011 socket macs.
a sixcore processor should be faster on multicore-things - e.g. rendering - but it's also more expensive. you won't get double the speed for double the money...
also, keep in mind, that you need more ram for a processor with more cores (2-3GB per core for After Effects Rendering), and maybe a motherboard with tripple channel ram for a six core processor (not sure about that).
so, as i see it, the easy way to a pretty fast workstation would be a core i7 sandy bridge (maybe wait a few weeks if ivy bridge macs come out) processor (e.g. 2700k) on a 1155 mainboard, the hard, more expensive (but within your budget) and probably even faster workstation would be a 6 core processor on a 2011 mainboard.
don't know about thunderbolt - there are some mainboard from asus, msi and intel out with thunderbolt - all socket 1155 - and gigabyte will have some in the near future (
http://www.techpowerup.com/165976/GIGAB ... rbolt.html ). but don't know if anybody got it working on a hackintosh yet.
please show me the other threads, i'd also like to know more on that.
