I'd consider selling it. I'm sure there's a 100lb GIS gorilla that would snap you up. Have you tried waving it at them. I'm afraid the only one I know is MapInfo who I'm sure got bought out by Pitney Bowes back around 2005?
This assumes the purchaser isn't just shelving it and killing off a competitor.
It't not an awful idea, especially since you know your competitors in the space (who to target).