Brodit/ProClip has finished two holders for the N1. They have a standard holder as well as a powered version. The powered version is real nice if you're using BT in the car and don't need audio out on the phone. What I haven't seen on their newer phones is their HTC cabled one that gives you the triple output of mini usb for power, headphone jack for audio and the usb headset. This is nice because you can run power and audio from the cable and only have one cable running up to the phone. I'm trying to get them to sell the long cable separately so people can do a nice clean install. I'm also trying to get them to do an adjustable version with that connection so you could use any HTC phone with the bottom center mounted connection. But at least selling the cable separately would be a start.
The two holders below are not yet available on ProClip's site. Haven't gotten an eta yet, but it should be soon. If anyone's interested and wants to save a few dollars, let me know.