On-One do a really nice 14" frame, I've just built up one of their 456's for my wife (she's 5'3").
They have a useful sizing guide on their site, showing photos of different size bikes with their owners: http://www.on-one-shop.co.uk/?page_id=940
I'm 5'3 and I ride a 49cm road bike. I'm guessing you're probably just a little bit shorter than me.
Have you looked at Redline's Monocog 26er, or the Jamis Dragon or Exile? I have a Monocog and Dragon - both 15inch. They are both awesome bikes and very fun. The Monocog is very very heavy (and inexpensive), and the Dragon is very light (but more expensive). I love ride quality of steel bikes.
A forum community dedicated to Mountain Bike owners and enthusiasts. Come join the discussion about bike parts, components, deals, performance, modifications, classifieds, trails, troubleshooting, maintenance, and more!