I've uploaded the parts list here for convenience of anyone wanting to build the GMK 6400 Mobile crane (MK III version). This MOC is a community project and credits should go to Gerger, Blakbird, AFOL1969, (and others) for the design and the detailed instructions. Refer to the eurobricks thread for this MOC here http://www.eurobricks.com/forum/index.php?showtopic=99748
This parts list here is for building the MK III version with Firgelli actuators. The MKIII carrier version does not contain suspension and is considered more reliable when driving. The superstructure is intended to be used with Firgelli 100mm linear actuators. The zipped PDF instructions can be downloaded here http://bricksafe.com/files/afol1969/Instructions/Grove6400-MKIII_1.1.7z
You will need at least ~5m of some custom string for the boom winch. Tying multiple lego strings would probably not work. However, I think you could use standard lego string for the inner-most telescoping boom.