Why not OpenSource Monkey? You have built a great ecosystem and user base. It stands to reason that others would be willing to help fix the paper cuts and bugs. If the commercial business is not working out, don't let this software become vaporware.
You could also pursue a model similar to what Red Hat or JetBrains offers: move to a subscription based approach that requires customers to purchase yearly renewals to receive updates. Just saying, that rather than throw in the towel, make a few changes to your business model.
Lastly, what about something like Kickstarter or another crowd funding system?