Do you like the Woods? I know that this is a crazy idea, but I'm going to throw it out there. How about converting the six footer to a five footer?? I use a five foot one myself on a 35 hp tractor.
Blades for rotary cutters are sold in lots of lengths. Look in a tractor parts catalogue (probably not the Woods catalogue) and see if there is something useful. I was amazed at the number and types of blades available.. New blades are not very expensive, and nice to have anyway. If you wanted to continue the project, you could have a local welder move the two sides of the mower inwards...its only a lip that needs to be moved..