RE: Update...(Kind of)
It might be useful to have one material in the exterior and another material on the interior and specifically when it comes to not wanting to refinish it, you might not want to use carbon fiber on the outside. Not really sure if that would cause more or less drag.
In theory, you could. Have to be careful with material choice since dissimilar polymers have a tendency not to want to stick to each other (exception is PEI). ABS/ASA would work for the outer shell and PC for the inner shell. You can then smooth it with acetone since PC is resistant (it will craze if you get carried away though). It guess it would have to be ASA since the rocket gets exposed to a lot of UV.
Hmmm... I might try this. Interesting idea. I expect it would be somewhat similar to fiberglass over phenolic tubing.
I imagine it might also be interesting to experiment with mechanically pre-interlocked parts for dissimilar materials that otherwise don't stick together well, though of course you'd still need to have at least enough adhesion for the first few layers to stay in place if both materials weren't extending all the way to the printbed.
RE:
Note that those who ordered FE version are more or less "beta testers", or with other words "guinea pigs" and that alone is enough to lower the initial price of those kits...
I hope that truth is not ever worse: that FE users are "alpha testers" and we are beta ones...