Hoser,
I agree with Tinker. I would also add that Pedersoli makes a nice hammer double. You can often pick them used for a couple of thousand. The prices for their new guns are now in the 5K range. Cherry's carry them on special order.
http://www.cherrys.com/ped_cart.htmUnderstand, that caliber often impacts the price of a double rifle. A 45-70 or 30-06, in general will cost less than a 470 NE. You can give Ken at Kebco a call. He carries Chapuis.
http://www.kebcollc.com/If all you want to do is try a double rifle out, then go with a o/u like the Valmet. The Baikal and Remington Spartan are basically the same gun, perhaps more QC with the Remington version.
If the idea of a sxs appeals to you, and you still want to save some cash, a cape gun may be the ticket. A cape gun has 1 shotgun tube and 1 rifle tube.
The other alternative is a rifled sxs shotgun. RBL made a 20ga. I have handled it and a few others. For the prices, I preferred a sxs rifle.
You may want to ask over at AR's double rifle forum:
http://forums.accuratereloading.com/eve/forums/a/frm/f/760101804Or at the Nitro Express double rifle forum:
http://forums.nitroexpress.com/ubbthreads.php?Cat=Pete