Is a mobile layout meant for thumbs typing or 10 finger?  If it's thumbs, then there isn't really much reason to favor colemak, and I would say that you should just go with whatever the qwerty implementation is, changing the letters to colemak.  That's pretty much the colemak style, and the purpose would be more to be learnable for colemak users than to be optimized thumbs.  If you want an optimized layout for thumbs you probably want to maximize alternation above all else, which is something colemak doesn't do at all, except in the case where it alleviates a "same finger" by (by luck) splitting the digraph between the hands.  Dvorak does do this and so would be better for thumbs.

If anyone cares, there seems to be 2 apps that add colemak support for android. AnySoftKeyboard has the Alternative English layouts pack  that includes colemak and DVORAK. Also Gesturekeys seems to come with a colmak layout option.

Now if we can only get colmak on Swype or SlideIT, and we would be in hog heaven.

That's awesome! Might even get me to abandon my own layout on my PC and switch to Colemak.  I've been meaning to give Colemak a fair shot and compare it to my own and being able to stare at it all day on my phone would definitely help me learn it.