You can negotiate even on leases. Especially in this economy. I know my friend sure did. Obviously they won't give the same kind of discount as you would get if you were a cash paying customer but you can still shave a few thousand off the dealers best price. Especially if your a customer with good credit and the know they won't have issues putting your credit app through they will budge for sure.
The other thing obviously to negotiate on a lease if going through an outside bank and not BMW for the lease is how much per mile if over the max limit and the oh so important interest rate. But usually no bank will be able to beat BMW's own in house financing rates and conditions. Only people who's credit BMW won't approve have to go to an outside bank so this won't even be an issue if BMW approves.
Again never leased myself but I kind of went through a lease on the sidelines with a friend on a new Audi S5. There in-house finance company was VW Credit since they are the parent company.
Personally I bought an Audi once myself with 75% cash and 25% remaining finance and I negotiated on the price, fees and interest rate. Same thing on my other couple vehicles. Dealers love cash buyers... thats when you can really get some serious $$$ knocked off the price.
I think the big thing with dealers is when a customer with little down and or below average credit walks in they pretty much know they can get you for how much ever they want because well you need there help at that point to get the vehicle.
