I think the most likely scenario is dealing his contract over to a team with cap space, to acquire the trade exception.
The only reason I do not think this is a really likely option is that there are very few teams with that kind of cap space remaining. Given the value in a trade exception like that, and the likely-hood that it would still eat up a few million of their cap space after a buyout, the C's may have to pay a premium to get it done. I am not sure a couple million, plus a second round pick would be enough, particularly at this point in the offseason. Teams have often gotten first round picks out of deals like this at the trade deadline, and they may balk at doing it over the summer and not even getting that.
And, if Danny uses a first round pick just to get the trade exception, he will have very few assets to combine with that trade exception to get a quality player for it later in the season.
I hope I am wrong about this, but just don't think its that easy.
Washington, Sacramento, and New Jersey are all teams with the cap space to pull it off right now. SAK and NJN each have about 14mil to spend, meaning they could absorb Sheed's deal and still have plenty to spare.
It's unlikely their looking to do much with that cap room right now, as the FA market is pretty much picked dry, and both teams have young talent they'd rather give PT to to help them develop.
You have a point that they might keep it open, and try to net a 1st round pick at the trade deadline, as the third team, in a 3 team deal that can absorb an expiring deal, and allow another team to acquire their player. But, I don't think it's completely out of the question that they wouldn't consider doing it for a second rounder.
You have to consider the only cap hit they take is his buyout prorated over the next two years (length of his deal) so if he buy out for 2mil, the team only takes a 1mil cap hit over the next two years. Not a terrible price to pay.