Two thoughts:

[1] Cast polyurethane resin with hollow microballoons (microbulb filler) is light enough to float on water, so the nose cones--even if solid--need not be heavy. (If someone needed extra-heavy nose cones for ballast/balance purposes, the resin "blanks" could be filled with ceramic microspheres or metal powder to make them denser and heavier.) The nose cones (and boat-tails, body tube adapters, and even scale fins) could be machined out of "blanks" made of microballoon-filled resin (for lighter parts).

[2] Maybe those of us who want custom nose cones from Semroc could chip in as a group (along with Carl & Co., if they're interested) to buy one of these machines for/with Semroc? It wouldn't take long for us to order all of the custom parts (not just nose cones) that would make it worth our while (perhaps they could "pay" us in a certain number of free machine-made nose cones [and/or other parts] per subscriber).

If we did something like that, I would suggest going with one of the larger machines. :) They also have a scanner function, so you can scan an original (oop?) nosecone and copy it. They also are capable of machining metal. Still under 5,000? I think

Then again, the whole reason I was on this company's web page in the first place was because I was following a link for a desktop printer which prints with white ink. It's way too pricey (it prints on anything, like cell phones , wallets etc.) but as long as I'm dreaming. ;)

Intriguing idea . . . would it be legal to copy the CAD software, so rocketeers could do the design work and submit the files to Carl & Co.?

I don't know, but maybe (to avoid copyright problems if there are any) it could be set up in such a way that we could design our desired nose cones and/or other parts on a page on Semroc's web site, which we could save on that page, and then they could use the submitted file(s) to machine the part(s)? I think Semroc's custom nose cone designer already works this way (although my old computer can't seem to "get with the program" [no pun intended] to work with their nose cone designer). :-)

If a larger machine would be prohibitively expensive (which I don't know), a back-up option could be to machine larger nose cones in two or even three sections (tip-middle-base section) using the small machine, which could then be glued together.If they have a used "floor display model" in a showroom at their company headquarters, you might be able to get it for considerably less (I got a professional 4-head VCR cheaply that way).