Cox service here in Gainesville FL our Cox TV Guide is in SD format which is a headache to look at on an HD TV. Any cities served by Cox have an HD TV Guide? I would imagine the big cities that Cox serves have an HD TV Guide?
An update it seems the 8642HDC DVR the newest DVR offered by Cox by Cisco had an HD guide. The only issue is the HD Guide doesn't fill the entire screen, but a good step forward. Also the older SA dvr boxes (some models) but those DVR boxes are pretty outdated.