I'm not a designer, and I feel my skills in Photoshop aren't perfect, but it is enough to design a skin for LMCE. I guess the harder part is digging into HA Designer and build a completly new skin. I recommend doing all the graphic stuff first (Mainmenu, Floorplans, Remotes, etc..) and do some testing with new objects first (for example, I like to have some kind of dropdown for User and Room selection instead of a seperate screen...).
Currently I'm building a bunch of Photoshop templates. Design single screens and elements and slice them according to my needs. With that done I only need to open a screen within Photoshop, press export and I get all the smaller bits exported into the correct location.
I hope to have the major part done the next weeks, I then suggest to move the templates to the linuxmce.org server, so people willing to help can jump in and help finish a completly new skin.