$899 is fookin' INSANE. There are plenty of AW mobos available, some even around the $200 mark. And a reasonable person will charge somewhere in the range of $175 to $350 to do the consolization, depending on what options you want (i.e., NeoBitz board with s-video, component, etc).
I got my set-up, which included a new motherboard and consolization--consisting of parts and installation of RGB output (I use the AW's native VGA output), power switch, test and credit buttons, a power supply, as well as wiring modifications for 2 Dreamcast sticks, and I got it all for $450 (not including the controllers, which I got on eBay for about $60 each).
If you're really interested, take the time to inform yourself. There are lots of resources on the internet and plenty of alternatives for you to choose from. The games are expensive, but the VGA output looks really nice, and I enjoy playing them in their original format. On the other hand, I don't condemn anyone who wants to play the ports. It's your choice.