Well, the newest MAD II design is basically identical to his old Marauder designs from his freelance days.
Well, it is the same artist ;D
The reason he got the job in the first place was almost everyone loved his fan renditions (not that you can tell with the comment
now ::) ) but I remember it being posted in passing that there had to a be a distinction between his fan work/commissions and the official CGL designs. So if CGL wanted to commission you for a
new Goliath based on your current work, they can.
It's also been mention CGL won't touch fan designs to avoid possible future complications.