Thanks to everyone for your input, it’s been very helpful. I’m going to take another crack at this…
Rocket Facilities cost 3/3, or (with Improved Construction) 2/2 or 6. I still think the facility should take two turns to build, but if others think it should only take one, there’s no reason it can’t just take one turn and cost 6 (5 with Improved Construction). Facilities can be built in any territory owned by the player that is in supply, have a max damage of 6, and have inherent AA.
The rockets themselves cost $1, and have all the usual abilities as described in the v3 rules. Facilities can fire one rocket, each player turn.
I’ve reduced the cost of the Facility from my original estimate and kept the cost of rockets very low to keep rockets a viable alternative to strategic bombers (thanks for the number crunching, @CaptainNapalm). I do accept that strategic bombers may be the better option though.
@sjelso You’re correct, they were, but they were more tactically mobile than strategically, as far as I understand, although I’m no expert. Maybe (as @Trig suggests) Rockets should be a type of unit, perhaps only available after the initial building of a Facility, but with no additional costs?
@insaneHoshi I like the idea of a technology countering the other, and there is certainly precedent, but when it comes to GW’36, I think Strategic Rockets means V2’s exclusively, and not V1’s, although I do see the merits of your suggestion.