Why events may be lining up for a major bond selloff...
1. New round of quantitative easing could bring dollar and bond selloff, as QE1 & 2 did. Bonds rally in anticipation and sell off on fact.
2. Bonds have massive capital gains this year, and any raise in cap gains taxes related to "fiscal cliff" issues could lead to massive selling before year end to lock in low cap gains rate. This would hit bond funds especially hard.
I think a case could be made for a rally in TBT to the mis $70s, at least.