what software are you using for your HTPC? MediaCenter PC? MythTV? something else? and also what OS, these may help in opening up your options.
I had my HTPC (mythtv) setup to a 16:9 project via S-VIDEO for a while, until I could find a 15" VGA cable, and MythTV had a skin that changed it to 16:9, and I edited my setting for X11.