I was given the question of whether it is possible to use a circular pattern, to array a series of identicle assemblies in a circular pattern and be able to have the diameter of the circle driven by the number of instances of the item.
Is there an equation/designtable/whatever that can allow for this? Is it possible?
Yes it is absolutely possible.
Create a circular pattern, then open the Equation Editor.
http://help.solidworks.com/2011/English/solidworks/sldworks/legacyhelp/sldworks/parts/hidd_new_relation.htm
The pattern diameter and number of instances should become shown in the graphics area by double-clicking on whichever feature contains the information. Once shown, they can be selected to populate the equation editor.