I have shopped 1 dealer and am waiting to hear back from 2 others re: a buyout on our X5

The first dealer said the numbers don't work (and also said no choice but to wait to lease end). So my question is at what point do they work? WHAT MARGIN IS NEEDED TO MAKE THE BUYOUT ATTRACTIVE WITHOUT A PULL AHEAD PROGRAM? Here are the specifics:

Our lease terminates 3/15/12. 3 payments remaining.
Buyout now, incl. $1,500 in property tax, is 49,074.00 (was $51,112.90 when 1st dealer rejected a buyout). The retail price for an equivalent CPO car appears to be $50-52k. Minimal investment needed to CPO our car since I took off the OEM run flats at 50% tread and will remount them for turn in. The 20 inch wheels have been repaired from curb rash, and there isn't 1 ding or scratch on the car. A good detail and a new set of mats should do the trick. ALSO, the car has never been in an accident.

What incentive does the dealer have to buyout the car now at say $47,600 (after I pay prop. tax) or even $46,700 after I make the Dec. payment (waiting for a new BMW to come in), when they can just wait it out, and buy the car out in March at $44,900?

I'm looking to utilize the holiday discounts to get into a new BMW lease and delivery is required by years end. A new x will take 4-5 weeks to deliver. It's s&$t or get off the pot time. I'll order a car tomorrow if I can get a bid to buy from a dealer on our current car.

Getting replies on a meaty question like this is what the power of these forums is all about. Any responses are greatly appreciated.

Happy holidays,