Billy you could try this neat idea for a topbox and i think a couple of sizes larger would be even better.

I agree having sat on one here this week. I found the seating position very roomy, not overly sporty, @ 6ft 105 kg I like roomthe kid wrote:Checked out the 14 on Sat and was quite suprised at how compact they seem when sitting on em .
From Shadows reports they seem the goods .
I want one ....................... as soon as they work out the luggage carrying details .