I’m 5’3” with 28” inseam and 185-190 lbs ready to ride. Ride a medium Ibis Mojo 3, small Santa Cruz Bronson, occasionally rides the wife’s small Santa Cruz Tallboy 3 in 27.5+ Version. Check out the SC Bronson or SC 5010.
A 63 y.o., 5’5″ with inseam just below 29″ who rides a rigid Mukluk (size small) fatbike set up year round (winter 26X4.5″, summer 27.5X2.8″) including a supported GDMBR over 43 days last summer. You may have to stay with 26″ wheels (or possibly even 24″) but there are OEM that have XS frames with sloping-dipping top tubes for better standover. good luck.
Fatback Corvus is available in a 14″ frame. Their fatbike frames may be most beautiful ones currently on the market and they will ship out of Bend, OR. (nearly purchased one of their new red/black ones tho the Mukluk won out on mounts for self supported trips/girth of the down tube-fat tires sure spit up mud).