Yep, I have a 4x2 RBI cage in waiting for when my female tops either 2.5 feet or 1000g...whichever comes first. Right now, she's in her 20L tank (they're 30x12x12 BTW) and doing great!
For my little male, I'll be keeping him in his 10g until he outgrows it, then moving him to his own homemade 3x2x1 display cage, which will probably hold him his whole life since males stay smaller than females.