I had something very similar to the OP link years ago, the Genesis Croix de Fer... in fact it looks like pretty much the same thing (triple aside). It was very heavy, to the point that on very hilly rides it gave me knee problems (maybe a triple would have helped). I didn't find the longer wheelbase life changing, in fact I never noticed any difference and the mechanical disc brakes (I tried them all: TRP, Hayes, Juin Tech, Shimano...) weren't any better than rim brakes... if anything the semi hydraulic like TRP HyRD were less reliable... basically a prayer before any squeeze of the lever, as I never got the same reaction twice.
Don't bother