Futures are up because people are buying stocks. GM is bankrupt today, but that was a foregone conclusion when the bondholders did not agree.
I am on the sidelines, and not buying FAZ until I see a real indication that financial sectors stocks are done. I have tried before to short overvalued stocks as they inflated, only to be hurt by the bubble blowing bigger, faster. It is fine that you think GM's failure will be the pin, but I think you are pinning a lot of hope on what is likely to be a non-event for the market.
If you think that all the money is in and the market is ready to drop you are missing the 401K and IRA picture. I had previously pulled my 401k into a cash holding. I just put one-third back into the market, as of this morning. There is some money on the sidelines, and it may go in favor of the longs.
Put me in the camp that says today is going to be another down one for FAZ.