I'd imagine that it should be conceivable to run Docker, and that THAT would be a preferable approach, involving running ARM code as opposed to x86 code (because emulation would be hyperexpensive).

There certainly is a port of Docker to RPi  <https://resin.io/blog/release-docker-0-7-2-for-arm/>, which points towards it being plausible to use Docker on various Linux distributions that run on RPi.  It's an interesting question whether or not that's much use for more mobile devices, e.g. - whether or not they're running similar enough instruction sets.

I wouldn't expect the other virtualization approaches to work out terribly well; they tend to be hungry for memory and storage space, which are exactly the things you don't have plenty of on phones/tablets.  (Leave aside the thought that some of the virtualization systems require hardware support that's unlikely to be present on ARM.)

Here's a bit of description on what's good/bad about Docker on Raspberry Pi...  http://blog.xebia.com/2014/08/25/docker-on-a-raspberry-pi/