I have been thinking of adapting copy cameras for enlarging too.

Since there are no condensers for a 24X24 enlarger, to my knowledge, that leaves a diffusion light source. That could be accomplished in several ways. The easiest way would to build a light head using fluorescent lamps as one method that comes to mind. The problem with this is that the lamp output is relatively low as far as enlargers go. In fact I am not even sure that a bank of fluorescents would be up to the task.

A typical 8X10 enlarger will use 1000 watts minimum with 2000 watts not being uncommon. When encountering lamps in this wattage the primary lamps that have instant on capability are halogens. This would require a mixing box to even the light out with diffusion at the light path exit onto the negative. A reflector of some design would be required to create a larger effective light source.

If a shutter were incorporated then any number of lamps could be used since instant on would not be required.

Fan cooling would be required.

All in all it is worth the effort if one is wanting a LF or ULF enlarger. If I were doing this, I would build the beast to enlarge 12X20 negs and advertise the service to people who wanted really nice big prints. If I were building this type of capability then I would opt for about 4000 watts of halogen...(four lamps of 1000 watts each) I would project these into a ceramic mixing chamber and plan on about 300 CFM of induction cooling.

I wonder if roll paper comes in 48 inch widths?