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.