As I'm planning on getting an Xpan camera soon, I needed an Xpan negative carrier for my Beseler 23C enlarger. But Beseler doesn't make one.
No problem, I bought a standard 35mm negative carrier off of ebay (8053) for $10 and sent it to SK Grimes. For $65 they machined it out to 24mm x 65mm. They did a super job!

This is cheap considering that the Beseler 4x5 Xpan carrier is $170 from B&H!

http://www.skgrimes.com/

Any enlarger that can do 6x7 and that has a 35mm negative carrier can be modified in this way to handle Xpan negatives.