It can be done, but not a direct swap. It's expensive and time consuming.
There's a custom 'busa which made the rounds at the International Motorcycle Show last season which has a tail closely resembling a Gixxer.
There are numerous pix of it here on the site...frankly, you won't like it...I don't. It's green and white, has a knock-off Louis Vuitton-ish seat, clear acrylic wheels, etc.
Yuck.
Anyway, there are a number of other things you can do to a stock 'busa tail-end which changes it's appearance. Take a look through the members' pix...like mine for example.