LAST EDITED ON 08-22-11 AT 08:19 AM (EST)A pipe dream? All Jeff needed from Porsche is that she vote against Rachel instead of him. That, to me was a very realistic plan. Unfortunately, nominating her made that less likely.
The show hasn't shown Jeff being onto Shelley and approaching Adam so I can't comment on that except to say Shelley and Dani (and the DR!) could also work on the floater.
There's nothing that Jeff did that prevented Dani from wielding that veto because she had a veto card. You plan on backdooring people to prevent them from even playing veto, leaving them totally defenseless like Brendon was. Not nominating Dani did nothing for Jeff but hurt him.
For Shelley, being 3rd in as loose an alliance as Porsche-Dani instead of 4th (not 3rd, no way) with JeJo-Rachel, I don't think she should hesitate one second. Especially since Dani and she could consider each other their perfect goat, having made many more enemies than Porsche who just bored everyone.