Thanks Dave & Eric,
As always, I appreciate your two cents.
Yeah, I was a little disheartened to make my HX discovery, but I haven't written it off yet - correct me if I'm wrong, but beyond the boiler, group, element and HX, everything else is replaceable, correct? (I realize switches and other assorted little things are likely discontinued, I'm thinking more along the line of parts that are "deal-breakers" with regards to restoring the machine).
On a whim, is there anyone out there with a "parts" Caffarex?
I've found a local company, All Weld (http://www.allweld.ca/) that looks like it might be up to the task of repairing the boiler - I've yet to touch base with them, but hopefully I'll be able to over the holidays. From the looks of their website, they're competent with pressure vessels and "unique" jobs. I'll be sure to keep everyone posted.

A little late to the party here...it seems that you are on the right track going professional repair on the boiler. Reject any notions of fixing the fitting with JB weld or other epoxy cure. The fitting would be easily enough brazed or soldered from the outside to build it up with a string shoulder and make sure you use a counter wrench on the fitting when you install the cap nut, which is recommended for all fittings. The hx could also be soldered, if you are talented at soldering, and for this job I would use a heat gun and not a propane torch as the metal is very thin, but a certified welder should be able to weld together an aluminum beer can (after emptying the can)....it is part of passing welding school and about the most difficult thing you can imagine.
All the rest of the mechanical and control parts on the machine are fairly standard once you get the boiler worked out.