There are a number of alternatives to the C*x glowhead, some good some not so good. MECOA says they will start making a real replacement glowhead soon, and they already make an adapter head for short or long plugs. In addition the Galbreath/Nelson combo is an instant hop-up for the engines, and very reasonable ongoing costs after the basic head purchase. Next, there is an excellent High-compression head clone made by:
Gerald F Boyd
102-7700 Francis Rd
Richmond, BC V6Y 1A2
I have run his heads, and find no difference from the original.
Finally, there are diesel conversion heads made by both Davis Diesel Development and MECOA.
As far as the supply of C*x engines drying up, there should be about 20 engines out there for every active modeler, or perhaps 200 for the active 1/2A modelers, as the company made over 1 million engines per year for at least a decade declining to about 10,000 engines per year at the end. I understand that they made a run of 250,000 sets of parts before shutting down the machinery for good.