Hey I've been playing around with mega x-compiling all last week.
I mass merged every cross compiler crossdev can build at this time.
http://tinderbox.x86.dev.gentoo.org/cross-x86/
I've actually got a crontab setup that will auto merge new cross 
compilers as they become available.

I've got a little script to also automate much of the process of 
figuring out what is the right x-compiler settings and what 
variables should be set.
I'd appreciate it if a few of you could take it for a spin and give 
me feedback.
It should auto detect if you have a crossdev x-compiler installed and 
use it. If you have more than 1 it would try to merge the package for 
each target compiler you have. In my case I wanted to install 
busybox/portage-utils/libc into every ~/ROOT-$CTARGET

It has a few quarks with merging virtuals and so on but thats not easy 
to solve as long as portage itself depends on /etc/make.profile 
symlinks.


-- 
solar <solar@g.o>
Gentoo Linux