
Darksol the Painbringer |

It's strictly a GM call.
If I was a GM trying to make it work, you'd have to isolate how much the +2 Dexterity would cost, which is tricky. In this case, I'd argue that it'd be ~6,000 gold, as both the Resistance Bonus (+2, but selective) and the Armor Bonus (+1, similar pricing to Bracers of Armor +1) would be ~1,000 gold each. And since chest pieces don't normally grant attribute bonuses, the standard cost (4,000 gold for a +2 belt/headband), the value is multiplied by 50%, leaving us with ~6,000 gold.
Now, bumping it up to a +4 would require increasing the benefit from +2 (and as such, the cost associated). This would boost the value from ~6,000 to ~15,000 gold, or having a total cost of 17,000 gold.
So can it be possible? Sure. But is it accurate, and should be done? Not really, unless you're the GM and want it to happen.

Saethori |

And since chest pieces don't normally grant attribute bonuses, the standard cost (4,000 gold for a +2 belt/headband), the value is multiplied by 50%, leaving us with ~6,000 gold.
While the logic is sound, I would like to mention that the whole "stats associated with particular slots, pay 50% more for unusual slots" thing was strictly a 3.5 thing, and did not get carried into Pathfinder.