Kinda depends on the bike you begin with. '80s MTB frames with high bottom brackets frequently had standover heights equaling much taller road frames. My 23" Cimarron is about the same as a 25" road frame (shorter frame higher off the ground equals taller frame). For your height you'd need a long top tube to avoid being scrunched up when riding, but a lack there can often be made up by a taller/longer stem to give you the correct reach.

If your bike is cheap enough it might be worth playing with, or you might rather hold out for something taller. They are out there. There's a 22" GT at our co-op and other brands made tall MTBs also.