I have not found a trap with a G Power number either, but I believe they make them.
When a Trap is placed on a Gate card it will open revealing either a different Attribute or G-Power. In a notmal battle, you woulld play with 3 Bakugan plus 1 Trap bakugan. When using the Big Game rules, you are only allowed 2 bakugan Traps. In order to play a bakugan Trap, you must have the same attribute as the bakugan in the battle that you want to use Trap with. Next you just lie Trap down on the gate card & when it opens, determine what is revealed, if it's an Attribute symbol, then your Bakugans Attribute is changed to that Attribute. If a G-Power is revealed, then your bakugan gains that amount of G-Power. After the battle, Trap goes to the used pile. When you are out of bakugans to use, take all of those in your used pile and move them to your un-used pile, you may also move Trap as well.
http://www.bakuganbay.com/Bakugan-Battle-Brawlers/Bakugan-Trap
There is only 1 G-Power giving trap in existisence (as far as I know) and it is a Custom Aquos Zoack 800gs.so No, there are no G-Power granting traps unless they are fake or custom (Still fake), there are only attribute changing traps.
I can say, they may make them but not they made or will make them.And 800g boost from a Trap will be terrible and probably a custom (Still fake).