Just my tiny MOD of a world famous mobile crane.
This MOC is a community project and credits should go to Gerger, Blakbird, AFOL1969, Krooshoop, Moittie, Albrechtfor and others for the design and the detailed instructions.
I personally only added counterweight, extended the superstructure and added the Y-arrangement for increasing lifting capability.
You will need at least 2x~3m of some custom string for the boom winch and Y-arangement. Trying multiple lego strings would probably not work. However, I think you could use the longest standard lego string for the inner-most telescoping boom.
Y-arrangements are the modified boom sections from the 8288 set.
You can download basic instructions here:http://bricksafe.com/files/blakbird/Renders/MOCs/42009%20Mod/draft4.pdf
After you need to open the additional instructions... Enjoy!