No way he doesn't end up in Dallas now.
Can they afford his current contract?
This will definitely be the sticking point.
With Murray signed for $8.4 million/year in Philly now (assuming it does not fall through like Gore and Matthews that is) It seems like the market has been set. Peterson was asking for $8.3 million prior to the deal with Murray being struck. So Peterson is likely going to want a $8.5 million type of deal now.
The Cowboys reportedly only offered Murray $5 million, which is why he walked. I do think the interest from the Cowboys is real, and that interest is mutual. So the $5 million may have been their cut off point where they would rather have Peterson if they were going to pay more than that.
I would think that Spielman and Jerry Jones have likely already discussed this issue at length by now. With some of the other RB contracts falling into place we may actually see something happen with Peterson soon.
Other teams that may still be pursuing Peterson are the Cardinals, Tampa Bay and perhaps some other teams we haven't heard about yet.