Hi i want to jack the back end up by about 50 mm, thought i could just replace the two dog bone linkages in the bike for some of another bike, anyone done this and whitch bike should i get them off ?

if you do a gsxr or sv shock swap it will raise it up..but i cant remember how hiigh

The SV shock swap mod will get you about 50mm lift. 
A Katana shock swap would give you somewhere between 15-20mm lift.

Here is the WIKI article on rear shocks:  CLICK