It's dead simple to convert them to electric flight. Almost all of my models I've flown as both rocket gliders and pusher electric. The build is nearly the same. I've made a small pod out of 18mm motor tube and 24mm centering rings with a $23 grayson microjet V-3 electric motor mounted that slides in and clicks into place in the 24mm motor mount held in place with the motor hook.
When you build the models you need some sort of BEC(voltage regulator) to power the receiver/servos from the battery, so instead of using a plain BEC, I just use an 18 amp speed control with bec built in. It doesn't weigh much more, and then I just route the wires back to the motor mount. When I fly on rocket power, the ends of the wires aren't used and they dangle, and I use a 2 cell battery for power. When i use the electric, I just plug in the motor wires into the esc wires that are there, and use a 3s pack. The electric is slightly heavier than the 24mm motor, but if I use an 800mah 2s pack for rockets flight a 3s pack for electric flight, the CG is exactly the same. I only need one motor for all my models and I just swap it from model to model. That's one advantage to having the motor in the tail of the model. They grayson will have unlimited vertical with a 6x4 apc prop and 800mah pack or larger with a weight up to 16 ounces.
Yes, as Mike says Motor setup cost is a hurdle. However you can't really compare it to a normal RC cost/flight. Compare it to a normal rocket flight. People don't think twice about burning $$ on casings and reloads for mid and highpower and after the burn, you are just watching it come down, with a similar flight time.....and then you have to go find it, with rc you don't have to go very far....A lot of people burn Estes D and E motors which are just as much if not more per flight....BTW, if you don't mind red arrow, their casings are $70 and reloads $18.99 for a 3 pack. It's really the cost of the case that bothers most people but it is machined from a solid piece with no forward closure instead of just a threaded tube. Cleanup is very easy, I just use a wet wipe, dry every three flights, but do relube the case each flight, just stick in the propellent, one o ring and nozzle and that's it.
People pay $50-$75 for an altimeter, some put a dedicated altimeter in each rocket... but might balk at a $75 computer 6 channel radio with 10 model memory...it's all just how you think and what you value, it doesn't have anything to do with what's rational
Quote from Mike: I'd worry that people might not want to invest in the AT E6 ($80.55 for the case and $20.69 for a three-pack of reloads at BMS).
If you want to fly electric, there are cheaper options. Flying RCRG requires a certain degree of something (motivation? masochism? I'm not sure what to call it) since the flight times are typically a lot shorter than what you can get with electric.
Mind you, I haven't done my homework on this topic, so please forgive the ignorance... How hard would these be to convert to electric? I'm imagining that it wouldn't be too hard to put in an electric motor and a light enough battery pack to fly this w/o the need to use a rocket motor. (for more fun... add in an 808 camera to the SR-71 and make it a real spy plane. :wink
Oh, and I've little fear of Testors' paint (except for the price).