I did it the other way round and when installing the 64 bit debian, grub found my 32 bit install and added it to menu.lst.
I have successfully maintained both systems current on unstable for over a year now. Most of the upgrading can be done from within the chroot, although occasionally I
have to boot into the i386 partition for some packages that need /proc mounted in the install script. At least this gives me an opportunity to check it still boots as
expected :).
Hi
just a question: why don't you just bind mount proc to your chroot?