App idea: CanvassStarter. Pick the neighborhoods your progressive organization wants to canvass; enter a question or two, and a bid for price per door.
Three or four organizations all want to canvass in the same place? Great--now we can all afford to do it! Not all their target voters are the same? fine by us! We'll use different scripts for those voters, and the increased target density will still make the canvasses cheaper for all involved. This leverages not just economy of scale, but economy of density.
CanvassStarter is especially geared towards relatively low-budget organizations looking to build a bridge between online and field (such as by building up a local organizing chapter around a high-energy moment or event), and for organizations who have a loose sense of others they'd want to partner up with, but who find it unwieldy to assemble coalition efforts due to the logistics field organizing and the complexity of ad-hoc coalition-building across different target geos and demos. So in this sense, it's like KickStarter for canvassing a neighborhood. And if you're one of the funders, your question(s) get asked.
We'd want to partner up with proven canvass-managing organizations, and there'd be some work to figure out what options are needed for neighborhood-based and voter-based bid options (like rolling our own Google Adwords bidding system, but not in a competition model, but then sometimes on a script-level basis in a competition-for-placement model). So the technical and logistical challenges are real, but mostly the service would attempt to stay lean and solve a lot of financial, political, and networking problems for highly aligned but distinct progressive advocacy organizations.