Many Canon EF lenses (inc non-tilt shift lenses) can cover MF, such as the 17mm TS-E. EG, the Hartblei MF camera with EF mount.
The 17mm in particular has +/- 12mm shift. The though TS-E 17mm is around a 67mm image circle iirc (vs 76mm circle needed for 72x24mm)
Otherwise a Super Angulon 50mm f/2.8 tilt shift lens should have a 120mm image circle, you can get them under $4k.. still cheaper than an Xpan setup.. probably.. but f/2.8 with a little movement left.
Otherwise, the Super Angulon 47mm f/5.6 will have loads of movements..hell it'll cover 4x5" You might as well still a 120 back with 35mm in a 4x5 camera.
Otherwise to keep it cheap, a Russian MF lens or LF barrel lens will do it for long exp.