yes it is possible. you need a little breathing room in your available DVR recording time (i.e. have 5-10 hours of HD time remaining).
This is annoying, and cumbersome but it works and i am now acclimated to it and don't think twice (well maybe, because if you don't you screw it up)
This is not really 'rotating between 3 tuners' but close. You have to record two of the Shows even if you don't want them archived. I just delete them when I move on to other programming.
It's probably not worth the trouble to you, but i dig it.
tune to Show A (Sat Tuner 1).
Swap to Sat Tuner 2, tune Show B.
Press Record for Show B.
Type OTA channel number (or search for it in guide), to tune *directly* to the OTA channel for OTA Show C.
Record OTA Show C.
-You are now watching & recording OTA Show C
-You are now recording Sat Show B
-The DVR Buffer is now buffering Sat Show A in background (or on PIP)
When you press Swap, you alternate between OTA Show C (recording) and Sat Show A (buffering). This only allows you to rotate between 2 tuners, Sat Tuner 1 (show A) and OTA Tuner (Show C).
But if you want to see the 3rd show (2nd tuner, Sat Show B), then while viewing OTA Show C (recording), go to DVR List, you will see Sat Show B recording, press "view" after selecting the recording.
Now you are viewing Sat Show B (recording) and can swap to Sat Show A (buffering).
To view OTA Show C (recording), view Sat Show B (recording) first, then go to DVR list, select OTA Show C (recording) and press "view"
confused yet?