I believe that sno-skinz used to make one, but all current models are seat only.
BRP also used to make one called the extreme cover that hooked over ski tips, but tunnel was still exposed.
If you're set on having your tunnel covered, a good upholstery shop can make an extension on a stock cover for you in a couple hours.
But that is on a short track. I bought the long track version for my 09 summit 154 and I could get it over my back bar. But that was pulling on it hard and I mean really hard! I always just wrapped it around my gas can instead.