How about getting brackets made and fitting something like this:
http://cgi.ebay.co.uk/ws/eBayISAPI.d...MEWA:IT&ih=016
I know some people will say dont use other Brands but thats just daft if they are a good/better than that offered by BM. I'd be interested in fitting some Porsche Big Reds or something like the Ebay ones above. I have experience of Porsche brakes (last couple of cars were Porsche) and they are superb...never fade, always reliable and great stopping power. Should easily be able to pick a Full set up from a breaker like
www.Porsch-apart.co.uk Either 993 Turbo Brakes, Cayenne Turbo Brakes or any that are the 6 pot front and 4 pot rear.