Hi all! I've pushed syscall and os package support for Plan 9 on x86 at http://codereview.appspot.com/3816043/ (pending a review). I had to make changes to the core go files, so keep your fingers crossed I didn't break anything along the way and get committed.
If you have access to a real Plan 9 machine or inside qemu) please test (9vx does not seem to work, confirmed by Andrey Mirtchovski for early versions of code). (Reminder: -s needs to be passed to 8l, otherwise the binaries fail to run). Thanks, Pavel