Ideas for getting an offer accepted?

[Todd Windemuth]

We are owners of 1/2 of a duplex (strange, I know). The other side was sold a few years ago (at a super high price) and the new owners gutted and remodeled it. They have now listed it and we are very interested in purchasing.  We offered (full cash) and after some back-n-forth counter offers we are still $10,000 apart on the price.  We've let it sit for another month and just reconnected again, reminding them that our offer is "still on the table" and we are willing to purchase.  They came today and countered with dropping down only $5K (not the 10K we need) plus free rent for 3 months while they find a place to live (which essentially gets us back up to the $10K that we are still apart).

So, any ideas of how to get them down? Our agent said that when she first checked back in with them, they were going to take it off the market and wait till spring to list it again...indicating that time to close and such is not a bargaining factor.  Anyone got anything creative that might help close the deal?