I had a buddy who dreamed about this when the iPad first came out.

Swift Playgrounds is a first step in that direction. There's still a lot of work to do, but you can technically write Swift on an iPad right now, so why not just add an IDE that will compile directly to device (no simulator required).

Would I be surprised to see this happen for an iPad 'Pro' a few years down the line? Nope, not at all, especially given how Apple touted that the Pro cpu specs can take on tasks once reserved for "workstations and PCs".