If you're in such a hurry to change modes so you can get back to the fight, it's much faster to land the plane and up a fresh one, than to taxi all the way to the rearm pad and wait 30 seconds to rearm then taxi over to take off again.
I've been caught in the same situation where I thought it was a GV attack (sometimes it was) and then it turns into a air battle. I either land and change modes/loadout, or just keep flying with what I went up with. If I run low on fuel or ammo I might try to land and get a fresh plane - sometimes I'll just stay and fight until I'm alone or dead, then get a fresh plane.
In my opinion, what you're asking for is not going to happen, and shouldn't. Same goes for all the wishes for a fighter rearm pad at VBases.