I made my own on the Cheap. Its not hard and does not cost a ton. The + side is one connection. It charges the phone, I get hands-free, and a wired stereo connection.
http://forum.ppcgeeks.com/showthread.php?t=49137
I have pics, detailed info, and a youtube video on my project. I have been using it with no issues for almost a year. I have been thru 2 phones sense my mogul and it still works. I used this on the Touch Pro and now my Touch Pro 2 (Sprint). This works on any HTC phone with the EXT. USB jack.
My youtube vid
http://www.youtube.com/watch?v=CfepHUE1EYY