No direct help I'm afraid Gaz, and I don't know what year/model Madone you're 'mates' after, but I used to have one of these, a 2006 model 5.5 Madone, (back when I thought carbon was the future

). Seriously though, apart from looking pretty dated now around the headtube and front fork the 5.5 is a great frameset, and looks stunning up close in Candy Red. Also the sizing is 'normal' on these as opposed to the later sloping frames. Mine was a 61, but when I tried the new Madone for size in 2008 I would have needed at least a 63!
Not sure these days but they used to hold their value really well. I know
you you're 'mate' only want a frameset, but if a bike came 'his' way, and FWIW, I actually much preferred the 2006 DA on this bike to the current DA on the CAAD10.