you mainly want enough blocks to fit the top of the mattress. then borders to hang over a minimum of 14 inches. most patterns can be altered this way. you usually just need to make more blocks than the pattern suggests.
is this the first one?
http://myolivebranch.wordpress.com/2010/11/
second
http://www.mccallsquilting.com/mccal..._Patch_Fondant