From their 11/2/2011 press release (http://www.amgentourofcalifornia.com/news/press/Thirteen-Host-Cities-Announced-for-2012.html):

“Tacking on an additional 10 miles to the route with the start in Ontario, Stage 7 will likely prove to be the penultimate stage once again.”

I’m not really sure what tacking an additional 10 miles on has to do with it, but it’s nice to know that the next to the last stage (Stage 7) will be the next to the last (penultimate) stage.

To quote Inigo Montoya, “You keep using that word. I do not think it means what you think it means.”

1. Next to last.
2. Linguistics Of or relating to the penultof a word: penultimate stress.
❖ n.
The next to the last.
From Latin paenultimus; see penult.

Perhaps you mean that Stage 7 will once again be the queen stage, or the most spectacular stage, or perhaps even the ultimate (in the best, greatest, or most extreme sense) stage, but its penultimate status is self-evident by its position in the schedule and nothing more; no need for likely proof.

Stage 7 could be a neutralized parade around the block and it would still be the penultimate stage.