mmmmmm technically the mod is not for sale yet so it is for me and I can just print them and people can request one from me at cost ????? 
It doesn't have the same impact without a logo of some type.
You might need to be careful... some of the big names in musical equipment are pretty protective of their logos/trademarks
I know that with Fender, any guitar manufacturer who does copies of their Stratocaster or Telecaster guitars are forbidden to even copy the shape of the Fender headstocks now! They are permitted to copy the body/pick guard shape but must use their own headstock shape.
Might be worth trying to get Marshall's permission to use the logo
the quadbox shape i'm guessing wont be a problem to use as nearly EVERY amp maker on earth has copied the slanted quadbox cab design at some time.
Having said all that though, i really like what you're doing with all these bits n pieces lately Swinksey.. keep up the great work
