just done something similar - found a scissor jack on ebay that's just 36cm long. it will fit inside the wheel, so I can store it in the gap behind the spare wheel holder.

Small Jack



"Y mae dafad ddu ym mhob praidd"
1972 4/4, 1981 MGBGT, 1984 FLHT1340, 1980 XLH1000, 1990 ZX10