DISH DVRs' guides have never had any ads, but you can't change themes unless you wanna take out the hard drive and screw with it there.
The only things you really can change are the font size (and subsequently how many programs are shown at once), you can remove the inset screen (who would want to do that?!), and modify personal channel lists.
I just typed all of that on my iPod, and I'm fed up with this keyboard. Rawr! Anywho, that's the DISH DVR IPG.