The Ducati Performance tailpack is excellent. It fits over the back of the seat with a flap and under the seat with straps. I find it doesn't affect the handling of the bike at all (and that's important for me). I bought a new one earlier in the year for just under £100. If your tent is small, you may be able to fit it into one of these, plus it is expandable. I managed to pack everything in for the Belgium Weekender last year (thanks Stafford for lending me yours
) and away again last weekend with my own (!) and still plenty of room left!