I understand that the there is an approved 737-700 AFM Appendix for operations on runways with widths less than 45 meters, but not less than 30 meters. This appendix contains additional cg limits, a Vmcg speed based on allowing only a 20 foot centerline deviation to retain equivalent safety margins, maximum crosswind limits, visibility, and MMEL considerations.
So you could always ask your airline to buy the appendix!
Mearse.