I have to disagree with your logic there. The average consumer would be more willing to purchase a cheaper bundle regardless of what came in it. Your everyday Gamestop customer doesn't have an easy time dropping $400+ on a handheld system. It wouldn't be that out of the question for someone to spend $150 on a system that didn't come with anything extra though.
When I say "premium" or "exclusive" I mean in terms of what they used to be...limited to pre-orders mainly. Retailers throw the terms around loosely like GOTY. With them being a limited supply the demand would be higher & these wouldn't be geared toward the "everyday customer". Moreso geared towards the people who got the 1st edition bundles.
They'd be able to promote the "at least a "$40 savings" line & the GC would most likely go towards more games/accessories.
You don't think a custom themed $400 Wifi/$450 3G vita bundle w/any 3 of these games Uncharted, MGS coll, Gravity Daze or Unit 13 & a 32 GB memory card would've sold at launch even with a $75-$100 GC?
$250 wifi $60 w/16 GB mem card
$300 3G/wifi w/$100 32 GB mem card
$40 Unit 13
$40 Gravity Daze
$40 MGS Coll