Part of me thinks that it is just the DUP playing hardball and trying to give the magic money tree another shake and trying to extract a better deal from the Tories.
However the Telegraph is reporting that informal talks with the Lib Dems have taken place. Again, I can't see this as a realistic option and seems more like a negotiation ploy to put pressure on the DUP.
Even so, interesting to see it all play out.