Has anyone successfully recovered empty stages in the stock game?

[Ulzgoroth]

IMO, unless you use a mod to automatically recover stages that enter Kerbin's atmosphere, the problem is unmanageable if you actually want to simulate it (since it will most likely require physics bubble much larger than 22.5 km, which could easily break your system).

Is there some reason the simulated zone has to be a sphere centered on your currently-controlled ship? In most cases, I'd think that replacing the 'automatically delete parts deep in atmosphere' with 'automatically simulate parts deep in atmosphere' would not be a serious processing problem.

Where it might be a problem is when you want to use non-physical time acceleration because your main vessel is now in space, but you have a bunch of boosters gently drifting to the ground on their parachutes requiring that the game do active physics simulation.