> Can I safely put a 64bit compiled kernel image into /boot/ along
> with /lib/modules<version> and the source in /usr/src/<version>
> into a fully 32bit image? 

Yes, as long as you don't have a 32bit kernel also in /lib/modules/* of
the same version.

> If so what other utilities on the system NEED to be 64bit for this to
> work? 

Assuming you have 32bit support in the kernel, nothing...

> I have a 32bit precooked image I use, and have dumped it onto a Turion
> laptop (see http://aenertia.net/megabook_m635.html for coverage). 
> 
> I am getting alot of issues with IRQ and USB f$%#ups. And am wondering
> if a native 64bit kernel will help. But want to know if I can simply
> drop an am64 kernel into the middle of a 32bit environment and have it
> boot? 

Yep, you can.  This is what sparc64 does.

> What is the easiest route for me to do this based on the above linked
> report.

You'll need to get an x86_64 compiler on your system (crossdev should
work fine, or you can modify gcc64), then you'll need to cross-compile
the kernel (there are plenty of docs online about how to do this).

--Jeremy