Absolutely and steerable tag's come as an assembly today, not as a cobbled together unit. Problem is, I've never seen any except for a class 8 truck.
Transit mixers (cement trucks) use them all the time. Basically it's a steer axle with kingpins and heavy springs attached to the tie rod that allows the axle to articulate when the vehicle makes a turn. You still get tire scrub to overcome the spring resistance but it's less than a solid mount.
Air bags and lift bags are still the best bet though that would entail an on board air supply and storage tank because, unlike air lift suspension bags, the air volume isn't static. It changes with load and road conditions and the dump, lift and reinflate cycles take quite a bit of air. Normally, any air axle will have whats called a levelling valve attached that allows air to enter or escape as conditions change. It gets complex because the systems must operate in harmony with each other.
Most likely more than the average RV builder would want to install.