I relocated my OnStar to the passenger side kick panel. The face of it is only attached with one wire and then the OnStar face plate comes apart and is actually very small you could put it anywhere. The metal box I tucked under my dash behind where you can turn off the passenger side air bag. It's not the best pics but you can see my mod here
http://elcova.com/groupee/forums?a=tpc&s=2826088551&f=6706011751&m=542107297 &r=542107297#542107297
Let me know If you need a better pic or advivce.