Making Tamales using a corn meal alternative
In some cuisines, the masa isn't usually corn at all. Sometimes it's rice, sometimes it's plantain and/or other starchy fruit. The tamale-like dish is actually called pasteles, but the difference between tamales and pasteles seems to be primarily the corn.

Check out this informational link and these recipes from Epicurious and The Polynesian Kitchen; and this video.

Making these wouldn't be like substituting a less than ideal ingredient for corn, because it isn't. Pasteles are a well loved dish in their own right. But once you know how to make the masa, you could certainly make a tamale recipe you like, but with the pasteles masa.