It has been done before but very much on a case by case basis- this was years ago when the company was a bit more friendly to the employees and rents were going up at a huge rate.
You would need to have a very good reason (marriage/divorce/baby aren't good enough apparently) and start with a letter to your fleet manager. Be ready for a firm "No" though. The people I have heard about being allowed to move back in (and I don't know of any personally) have basically gone into the office with a request to move back in in one hand and a resignation letter in the other- and been in a situation where they were quite prepared to hand over either.
Interestingly, the cabin crew are allowed to move back in. Go figure.