I have a spare CD drive bay I'd like to put a fan in,
don't need anything very powerful, don't want to draw
too many amps, but need it as quiet as possible.

Will be blowing in the general direction of one end
of the RAM and near the underside of the HD.

I've looked in several online catalogues, but can't
find anything for a CD bay, only HD bays.

Thanks for any tips!

The CD drive bays are very inconvenient and awkward places to cool your PC.

This is the only 5.25" bay cooler I know of. But I think you will be better off sticking with normal case fans for your cooling needs.

Yes, I think so now that I've looked some more.

I was thinking of something that would fit in a panel that blanks off
a CD bay, but that would put the noise up front by the user.

I found a 40mm case fan that's under 21db - I'll just cut a hole in the
side of the case and use it for exhaust. It should pull air over
the RAM and past the HD and CD so should work out OK, and be
quieter being off on the side.

My wife's going to use this for work-at-home so it'll be on for long periods of
time. Never had any heating problems, just want some safety margin.

Thanks for the input!