We've just posted a public beta of SkyDemon 3.5 on our Android page, which includes rainfall imagery. Please give it a try and let us know here how you get on.
http://www.skydemon.aero/start/beta.aspx

Great idea - and nicely integrated, although for some reason I expected the option to be under the map layers settings, not the weather settings.

There appears to be something odd rendering rain which spans the prime meridian though - there appears to be a very narrow band of clear weather due north-south.