A couple months ago I had to replace the laser tube/driver on my 35W Epilog Mini-18. It had slowly been losing cutting power for a few weeks before I had to get it replaced because I simply couldn't limp it along any more. I snapped a couple pics of the laser module before sending it back to Epilog to swap it out for a fresh one:
The entire module is housed in a big aluminum block and sits under 4 fans on the cutter for cooling.
The whole thing appears to be powered off the main 48v power supply and it connects to the motherboard via a standard Cat-5 patch cable.
On the opposite end you can see the laser pointer module, used to adjust the optics and help you position the laser home position. Overall, these modules seem pretty well designed and pretty convenient if you're building a laser cutter. I'd love to be able to find laser module setups similar to this (air cooled, metal reflector tube, integrated visible laser pointer, integrated driver electronics) for a DIY laser cutter!