A new player enters they fray
BMW E39 E53 GO Multimedia Touchscreen Headunit GPS NAV DVD CD Radio Bluetooth | eBay
I saw this on eBay the other day, they claim it comes out of the Dynavin factory, just with some features removed (not sure which ones). But $499 compared to $1299 is a big difference!
I've bought parts of them in the past (brake disks, wheel bearing, etc), and the service has always been exceptional.