It is _extremely_ viable: The core REPL functionality is based on a few ClojureScript lines from Joel Martin's initial work for something similar for Node.

In short, to make an Android version would involve just running a JavaScript engine and hooking up a little bit of UI to send strings to it, and get strings back out of it.

Replete is open source... feel free to steal heavily from it.

Look at how simple and rough the first working version of Replete was (see demo of it at bottom of http://blog.fikesfarm.com/posts/2015-06-27-replete-a-standal...)

IMHO an Android version is just waiting to be created by someone. :)