Yesterday I went to a DH bike park and rented a Kona Stab deluxe 2008 model.
Wow! It was so nice! It did everything I hoped out of a DH bike.
I am not exactly an expert, all I can say is that the bike rock gardens were gotten through and control was kept on the steepest gnarliest sections. I rode on their hardest run and the only weak link was my fingers and feet trying to cling on to the grips and pedals.
I paid ¥9000 for 1 days rental, about $90.
I am tempted to buy one of these bikes now, but I fear I won't go out to the mountain enough to justify it, so I guess I can keep on renting, and dreaming.