Frontier could literally just allow players to deploy and remotely pilot skimmers, similar to the way Ship Launched Fighters work... and as there are already several different types of skimmers in the game, that would give us at least 3 alternatives to the SRV instantly, with no new art assets or anything required!
Of course, skimmers wouldn't be able to pick up cargo, and they would probably run out of fuel more quickly, especially on high gravity worlds... but they would be fast and easy to use, and their weapons might be more powerful, too, so they would still have some utility over the SRV, especially in combat situations. (Maybe that's why Frontier never did this, because they would be too strong...? Ah, but I'm sure it could be balanced!)
I would like to see some new SRVs as well, but Skimmers would be a nice alternative... and any ship with a Fighter Hanger would probably be big enough to deploy a Goliath too, which is actually big enough to be flown in person, just like the SRV! (I know that the Goliaths currently in-game are not piloted, but they could be, they're almost as big as a Sidewinder!)