I have an air suspended fork and I had connected the air hose and bolted the pump to the fork.I could pump the fork even while riding, I could also let air out. On my setup after a while the hose connector started to unscrew from the fork valve, probably vibrations related. It could be screwed back in of course, but I lost interest, since I don't play much with the pressure once I find the sweet spot...
Still the idea is functioning.
If I had a way to extend my alu frame and the money for the parts I would do it like this:
1. Search for a an Y-hose for air line if available.
2. Get a couple of air rear shocks.
3. Get a car 12V operated tire compressor.
4. Connect it to a power source be it external or E-bike battery via step down converter.
Easiest and cheapest way would actually be to take an used air fork and use as a part of the rear extension for the action, shaft could go away. More or less something like the shockster, but with air:
But I think the main Problem with this design would be getting rocker plates to bolt on to the dropouts and then again to the fork. And they have to have droputs for the wheel... If it was not for this tiny detail one could use a (car's) brake pad.
Possible interference with the components of the brakes or gearing should be taken in consideration...