Well let me tell you, publishing to Windows Store is complex and was far from smooth. However I did it and now await their decision =D

Lot's of things that threw me with this one:
Huge install times (hours)
Problems importing the package.
Lengthy validation fail process and packaging.
Revision number kept firing back as incorrect. Revision numbers MUST have 0 on the end (i.e. 1.0.0.0) as the final 0 is reserved for MS use.

Plethora of new image (90+ so far) assets to create (there is supposed to be a generator tool, but it wasn't there so... manual)