Suse automatically detects the proper arch in the
boot-loader
for
some time now (you can override it, too, and install a i386
system on a
x86_64 machine).
Solaris also does this, boots off a i386 kernel and installs a 64bit
kernel.
that's different. For fedora... what'd be needed is a bootloader level
hack (seems SuSE already has one) and about 4 weeks of sleepless nights
for Jeremy ;)