Not to jinx myself or anything, but so far the upgrade of my domU from Debian Sarge to Debian Etch has been very painless. It upgraded over 200 packages, and I only had to manually resolve about 10 config files, most of which involved taking what the new package provided. After moving /lib/tls to /lib/tls.disabled and rebooting, everything seems to be working right.
Fingers crossed that it continues to work.