Sure, if you know which part number you need.  I bought a spare 3UZ ECM on UK eBay a couple of years ago (along with an engine wiring harness).  There's a group of guys who can flash them in New Zealand, Russia, California and the UK; they all use the same technique to remove the immobilizer and increase performance.  Gloverman and George_R on this forum can help you.  Good luck with your swap.
Ciao,
JZH