Im not sure how you would go about one, it cant go up and over the weber filters, becuase it will hit the bonnet, therefore it will have to go around either both one way or split one around each way like the very well draw pic below 
The red squares are the weber filters, i think ill have to leave it until next payday as this will cost a bit more to make im guessing, but if you could give a rough est, that would be good
