I agree with Lewis. Bass is just one tier above certified one-termers like Allen West.
Bass is several tiers above, considering that this is his seventh term. Non-consecutive, yes, but still. Seventh term.
For 2012 to be as ugly for him as 2010, you need to (ironically!) assume 2012 will be as ugly an anti-incumbent year as 2010 was. Bass isn't safe, but the assumptions that he's a goner require a number of different planets to align.
Bass ran an abysmal campaign in 2010 (again) and almost lost to an opponent with no prior elective experience and with far less money. He represents a D+3 district and he is ethically challenged.
I don't know what else he must do to be considered very vulnerable.