Ok before I even begin- I get that gadgeteer is already a VERY meta advantage and allows for the effective creation, destruction, and displacement of CPs advantages/disadvantages and traits.
Lots of fiction has expert/divine/infernal craftsmen/women/things who can alter the very nature of a person/place/thing's being.
Sometimes it is a bit easier to just move this into 'enchantment through crafting' or a powerful, open ended affliction of dynamic alternate form, but that seems to give problematic returns- its easier to turn the Argus into the peacock (net negative alternate form; 15 point total) then it is to charm the life of a worthy adventurer (15 points for alternate form, +15-120 points for luck and serendipity).
We already have examples of existing traits being moved into the meta range like detect [1], and some magic systems spend a lot of time in the meta realm (granting exotic capabilities in RPM casting generally involves 'figure it out in points and pay this much extra energy'); so I am wondering what moving gadgeteer into the meta range would look like, basically giving the gadgeteer the ability to work on, alter, and invent character sheet items directly (with the GM deciding how fantastic an invention that is).
[1]
http://forums.sjgames.com/showthread.php?t=71461&page=2