I am looking for a new universal optical disc player to mod. I want to
put in a good manual attenuator at least with a big knob on the front
and may consider other upgrades. Gary Galo did an article on CD players
a while back but it's been a while, and he uses a preamp anyway. Any
recommendations?

You have a point there. The Samsung I saw at a mass retailer recently
didn't seem to have a very rugged drive mechanism though. I guess
that's why it's $99.