My wildcard tip stage 6 is Arashiro.
Yes I'm a little biased as I have some Japanese connections (and the fact that he deliberately threw me his bidon last year coming back down after doing Andorra Arcalis last year - i might have cheered for him a bit on the way up

).
I know it sounds far fetched but here's my reasoning:
1. a breakaway has a good chance tomorrow as the main GC teams will(?) be saving themselves for the alps (and Cav's bunch may be a little tired after last two days).
2. Arashiro publicly announced he was aiming to be in the breakaway on stage 5 - didn't happen and Japanese honour will make him more determined
3. if he is in the breakaway and it succeeds he's a half decent sprinter
4. I just really want it to happen just to see the japanese go crazy about tdf.
Before you tear me down, I did say it was a wildcard. If you look at the profile it's a lot bumpier than what your first impressions may be so a breakaway has a good chance if they get the right mix. Anyway here's hoping.
P.S. first post - woohoo. Long time lurker and really wanted to post some stuff over last few days but unfortunately my opinions were a little strong for a first post