This. The only thing I use my pipe clamps for is glue-ups that are too large for my K-Bodies. I can't speak to how useful you may find a Domino down the road, as I don't have one and it's merely a ways down on my long list of future tool acquisitions, but I'd be far more inclined to simply give away my pipe clamps than I would to sell my K-Bodies even at 80%. The only clamps I use more often are my Quick-Grips.
That said, I expect that you should have no difficulty getting 50%, maybe even 60% on the Besseys or Jorgensens, 30-45% on Irwins. The Besseys' resale will depend in part on whether or not you have a lot of Lowes around that blew them out recently, if so, that may hurt their resale in the fairly near term. For the Domino, if you haven't seen any crop up on your Craigslist thereabouts, then you've got a good shot at getting 60-75% for it, possibly more. That, or squat. The market is either starved and hungry, or there is essentially no market for 'em in your area.
Go for it. If after you're done using the Domino and clamps, you either can't sell the stuff there, or decide you'd rather not hassle with it, I'll be happy to pay shipping and take 'em off your hands to free up space for you.