Hi Kelp, generally you can get backgrounds from anywhere that sells tropical fish. You can get black, blue, coral and plant looks (prob more but thats all I have seen). They can be sold by the cm, ft, mt etc.
As for the rams, my ram is tank mates with a dwarf gourami - they dont fight, often I find them swimming together, some guppies and some neons. He also shares it with a cory and a bristlenose catfish.
Rams are quite peaceful, so they should be ok with all of the above type fish.
My male ram was quite nippy with my female ram and chased her around all day. I think he terrorised her to death (she is RIP). Now he just swims around and doesnt bother anyone.