You have "/chroot" in most places, but "/var/chroot" for the fstab lines. They should be "/chroot" too.
I've followed this guide (more or less), and I can confirm that sound works just by mounting /dev. For the record, that's:
/dev /chroot/dev none bind 0 0
in /etc/fstab. (However, I also killed esd long ago, just to get sound working on the 64-bit side, and set everything to alsa then; I don't know if that makes a difference.)
I now have two chroots on my system -- /old32 and /new32.

(/old32 is where my old distro is, but I also need /new32 for more current software, like Acroread 7.) I added "-c new32" to my do_dchroot script, since I have old32 as the default.
Another thing I added is the "linux32" command (in the package of the same name). Put this before dchroot, and the 32-bit apps will think they're running under an i686 kernel -- which is necessary in some cases (mainly install scripts).
Re Flash, you can install it from Synaptic. In fact there are, confusingly, two conflicting packages. I chose the big one -- the small one is apparently just a wrapper for Macromedia's installer.
Themes are a little off for the 32-bit apps. But that could be an advantage, since it reminds me which version I'm using.
Now we need a list of what hasn't been ported to 64-bit. (Another thread, perhaps.)