Apparently rEFIt shows bootable partitions, from a quick glance over its documentation.
Also, TC doesn't currently support EFI, so you need to use Boot Camp, enable BIOS/MBR emulation, and install TC normally to the resulting partition (including a "normal" bootloader such as lilo or grub, rEFIt will chainload it). After that, TC should be visible in the rEFIt menu.
One can control the cpu/core where to run applications, but the required program is not yet included. The syntax would go
taskset 1 mplayer
taskset 2 firefox
for launching mplayer on core 1 and firefox on core 2.