Fortunately it doesn't work that way.
If Bush is removed, Cheney moves up and appoints a VP, If Cheney goes, the new VP moves up and appoints a new VP.
Only way Pelosi moves up is if Bush and Cheney are taken out together.
I 've said this on other treads here and it bears repeating...this is the start of a 10 year nightmare
Not quite. Cheney's pick for VP would have to be confirmed by a majority vote of both houses of Congress -- so if the Dems are trying to take out Cheney, they could bottle up that confirmation for as long as it takes to do it.
That's why Agnew got squeezed out in 1973: So Nixon could pick another VP and have him in place in the event of his own impeachment. If Agnew had still been in office when Nixon resigned, I have little doubt Agnew would have been impeached and removed from office.