I have just created a thread over at the XBMC forums regarding the RTSP issue, hopefully some of the guys there can shed some light.
RTSP from Mediaportal TV-Server not working - XBMC Community Forum
dubbeld; It may be worth getting in contact with BigBellyBilly over at the XBMC forum, he has created an EPG script that afaik utilises a GUI to display the usual EPG look we are all used to.
myTV v1.18 script released - XBMC Community Forum
Or there is also the mythbox script which presents a GUI for the EPG, screenshots and release links here;
[RELEASE] MythBox for XBMC (Alpha Release) - MythTV frontend Python Script for XBMC - XBMC Community Forum