I'm using an electric fan on my engine swap. I have the thermostatic switch, and the override. Unfortunately it's suggested that the fans be placed to pull air through, as on engine side of radiator. There are some low profile fans out there.

It's also possible to reposition the radiator farther forward, giving more clearance on a Townie. First option is to place radiator mounted on forward side of the vertical attachment ribs on radiator support, that gives up to 3/8" more clearance. Next option is how I have mine, with radiator mounted to front side of radiator support. Now the radiator is all the way forward about 3 or more inches.

I cut down the mounting wings on sides of radiator, set it in front of support, then fabbed some simple brackets that go from radiator wings to radiator support, all bolted firmly in place. Only drawback is somewhat limited clearance to fill radiator using stock trim piece on top, but it's very do-able.