Hello from Happy Hacking BB

[CheshireNoir]

Hey Eric,
For composite, I just bought an old LCD TV with Composite In. I think you can still buy them new if needed and I am yet to find a TV that doesn't work with the Composite out from the 'bee.

As for CGA, (Deep Breath) There are many, many options.
Turnkey, you can just buy an adapter from Ewan: https://microbeetechnology.com.au/vga-vi...verter.htm
You could "roll your own" by getting a CGA to VGA adapter like this one (https://github.com/necroware/mce-adapter works really well) and then either plug it into a 15KHz compatible monitor (http://15khz.wikidot.com/ Which is what I have done) or plug that into an upscaler.
As for upscalers, there are a lot of options out there. Personally I have a commercial upscaler for most of my stuff that I trashpicked from a refurb, but I also have a GBSControl (https://github.com/ramapcsx2/gbs-control) which takes a cheap chinese scaler board, sticks a spike in it's brain and parasitically replaces it with a new brain. The results are astounding, but it's a bit fiddly to build :-D

I, er, have a lot of different systems to support, so I have a lot of different solutions.

Hope some of this helps!

John