I'm wondering where TV Guide HD is for us too Mat - I spoke to a CSR about another issue and she had no clue saying she has had it for some time. As I said in a previous post, the delays with these new HD launches is getting longer each time.
I don't know Nascar - as for the TV Guide HD add, they just dumped MAV HD so they could easily have used that QAM slot.
Your theory probably does apply to local adds like WLNG but not in this particular instance - some VHO's have had TV Guide HD available for more than a month now. Also, Verizon had originally told us the MSG2+ channel would be added by end of 2012 and still nothing so they had that original reserved spot available for WLNY if they wanted.
Plus VHO 7 has the issue with Philadelphia / NY coverage - I'm in VHO 5 (NY) and we don't have that problem - we just have the continued slow roll-outs of new HD's.