I had one of these in my custom set from back in January:
http://www.bloomilk.com/Custom/Characters/705

Your take is pretty similar, but I made it a CE and only apply to figures with Master in their name:

Commander Effect: At the start of the skirmish, choose an allied character with a Force rating whose name contains Master. That ally gains Force Spirit 4 while within 6 squares of this character.


I did that because it was Yoda who learned Force Spirit, not some padawan. And actually, now that I think about it, I think a QGFS should function quite differently from the other force spirits. For example, Obi-Wan met up with Luke, whom he taught. But QG met up with Yoda, who was his boss. I like this take on Qui-Gon (it's pretty similar to mine after all :-) ), but I wonder if a new form of Light Spirit might be more appropriate to Qui-Gon:

Light Spirit 2 : Ignores characters and terrain. Cannot open doors. Cannot attack or be damaged, and does not count as a legal target, the nearest enemy, or adjacent. Not subject to commander effects. Does not provide cover. At the start of the skirmish, choose a Unique allied character with a Force rating whose name contains Master. That ally gains Force +3 and Force Spirit 3, and gains Mettle while within 4 squares of this character. This character is defeated if the chosen ally is defeated. An enemy within 6 squares can spend 1 Force point to defeat this character; save 11. This effect replaces that enemy's attacks.

Something crazy like that. Or give out Force Renewal 2 or Master of the Force 2. That would drive the cost up considerably, of course.