Looking for someone I can take my seat too (Along with my bike) and get them to either make a seat or refoam and fab my original as it is utterly uncomfortable! And the mrs always complains… 
Its a Bandit 600 Mk1 and I do have a shape in mind.
have a go yourself m8, use a bread/meat knife to cut shape, i prefert to do it in little bits at a time then when you have somewhat the shape you want use sand paper to smooth seat out etc.
i have done this to many a bandit seat and had good reults.
with the covering just pull out the staples carefully and you then reuse the convering and use a good stapler to re staple, not your desk stapler though, lol
Apparently it helps to freeze the foam first (if you can find a freezer big enough) as it makes it firm, so easier to cut and sand. I’ve recovered seats on both bikes and cars before and it really is no big deal so long as you take the time to get it done right.
For some reason that link won’t open for me… 
This is the sort of shape I want but not with the design, and I can’t be arsed to make it myself