how about looking into some dwarf croaking gourami (trichopsis pumilus)?.....they get to about 1 1/2 " inches and maybe two or three would do well in a 5........i've been considering some from my 6 gallon for quite a while but still haven't gotten around to setting it up.......as to being colorful, i wouldn't exactly consider them to be so although they are prettily patterned and their eyes have a blue sparkle when hit just right with the light.....
a really beautiful killie attaining a little more than two inches is the Cape Lopez Lyretail/Orange Lyretail (aphyosemion australe).....they are a fiery orange and red......i have no info as to their care/requirements, though.....i think aquaria central might have info on this one....
another great looking killie is Nothobranchius guentheri, which is "well suited for the beginner as it is hardy and easy to care for." (or so says my source)...gets to a little over 2 inches as well....