Have you purchased the fish, yet? If you haven't, consider that Bolivian rams are hardier than the German blue rams, grow a bit larger and it will be easier to find a pair of them (GBR's are mostly male due to hormone injections at the fish farms when they're young, similar to dwarf gouramis). However, I don't think they look quite as nice as the rams, so it's up to you. If you get two rams and you don't have a pair, be sure to divide the tank into two distinct territories with plenty of cover so that they don't do too much bickering.
Also, if you're still interested in jewel cichlids a single jewel in a 20g tank would be a very nice tank. They're mean fish, though, so I can't exactly recommend putting much of anything else with one.
Other cool ideas for 20g long tanks that I've thrown around:
-River biotope tank with hillstream loaches and white clouds and a lot of water movement
-Small species tank of dwarf shelldwellers like lamprologus ocellatus or lamprologus multifasciatus (hard to come by and need the right tank setup but are hardy fish and not difficult to breed)
-A sandy-bottomed tank that slopes down into shallow brackish water on one side and up to a beach surface on the other. Inhabitants would include fiddler crabs, mudskippers and possibly bumblebee gobies.