Well I went and looked really closely at mine. It appears that most of the sides consist of an upper panel and a lower panel. So if I took them apart, I would have two shorter back panels, two shorter side panels, and two shorter front panels that have doors. And the "frame" around each panel appears to be just three sided (top and two sides, with the bottom being just bare wire ends, not framed) The whole cage is held together with screws that fit an Allen wrench, so taking it apart should not pose a problem.
My husband looked at it, and he agreed that if I made a new back piece out of plywood, and a new base to put the wheels into and to support the whole thing, then I could reconfigure all the pieces and make a cage that is twice as wide as it is now. (The bottom shelf by the wheels is exactly the same size as the top panel, so that solves that part of the dilemma.)
Not sure I have time to take on another project right now. The basement is already cluttered up with all my other half finished ideas laying in various piles.

But I just emptied this cage out and it needs to be cleaned anyway, so I think I'll at least take it apart, clean all the pieces real good, and then see what I feel like doing with it.