Some will state larger aquariums are mandatory.
I wouldn't be too concerned about the dwarf cichlids such as the german blue rams or bolivian rams not having enough space. My bolivian ram is one happy camper in a 10 gallon I have housed with some rummy-nose tetras.
I'd recommend the bolivian over the german based on various articles i've read and the general concensus among some aquariums owners that germans can be quite sensitive to water conditions. Case in point, one of my LFS had a large shipment of german rams (~30 ) sent to him. Fully quarantined, yet within 2 days, they were looking worse for wear, within a little over one week, 95% croaked. Mind you, the germans are beautiful fish and if you cross your fingers perhaps you'll find a decent supplier or have the magic touch yourself.
Marc