Worst case scenario is that you have to put in a separate piece of carpet over the trans tunnel and butt another piece of carpet up to the tunnel. If the floor is relatively flat there should be no problem doing it in one piece. Here's a place in Newark, NJ, but I'm sure they're very expensive. Square Weave Carpet
Be prepared for some sticker shock, the lowest price I've seen for wool square weave carpet is $80 a yard, and I haven't looked for any in a while.