Nice idea. The Nokia N8 has this. ( I am an ex-Nokia technician :)) Two screws had to be removed on it but still, same idea. Instead of removing the whole back. Would give it a unibody look.
If this rumor will come true , i can say i love it
Removeable battery is a very good option for a phone
I think LG won't remove the back buttons. That is what makes LG phones better than the rest.