Not as rare as they used to be mate. Aqoutix had some adults in their top tanks and a couple people breeding over east so you should source some with a little effort.
I had a colony of these guys about 6 years ago now but unfortunately had to sell up. In regards to tank mates they are fine with anything big enough not to be considered food. Mine were actually very peaceful fish and I had no issue with more than one coloured up male in the tank.
Pretty easy to breed once of age and decent sized clutches - mine were averaging about 80 fry per mouthful and they were dead easy to raise.
One interesting thing, I was raising fry from about 1.5cm out the mouth and into an ibc cut in half with an inch and a half of coral sand on the bottom to grow them out to about 4-5 cm. they grew quick and the first time I went to fetch some out and sell them off, I had about 50 juvies in the ibc. I grabbed a couple of nets and started to herd them into a corner to collect and fetched a few on the first swipe and went to bag them. When I went back to the ibc I couldn't see a single fish in there and I wondered wtf they had gone. It took about 5 minutes and then they started appearing again. I watched closely and as I moved the nets the juvies were diving into the sand substrate to bury themselves and then wriggling up to expose just their eye on the surface of the substrate. As I looked closer I could see all these tiny eyes looking at me from the sand. I'd never heard of this in the Aristochromis and the adults never did anything like it but in the absence of a mothers mouth to shelter them, the fry had either learnt or instinctively knew how to find shelter in the substrate. I thought it was pretty cool.
Great fish, I hope you get some