SCORE!
Snagged the $150 discount on a $30 SERO plan. The retentions rep initially offered a $50 discount on the spot because my plan is already a steal, but I insisted that the phone was overpriced and that I was considering switching to ATT for the $100 iPhone. She put me on hold and talked to the administrators who she said are now price matching the TP2 upon request/cancellation threats.
Apparently worth a try even on a SERO plan.
Thanks for the thread!
EDIT: Probably worth noting that I have had the phone for a couple weeks and haven't sent in the MIR yet.