Dave et al, 
You can add me to the list of companies that will provide voiding data.  I am data mining variations of the print pattern to reduce voiding and I am in the process of marrying up stencil design to void and fill percentages.

I can echo the voiding request from Blackberry.  The original request was 90% coverage and no more than 3 voids with no single void greater than 5%.  Even to get to the 70%, I ended up using a custom solder slug and still had voiding due to via in pad.

I would like to see a standard that reflects something similar to the following:
Class 1: Undefined
Class 2: Shall be 50% coverage with no single void exceeding X% or as defined by customer or part manufacturer.
Class 3: Shall be 70% coverage with no single void exceeding X% or as defined by customer or part manufacturer.
Note 1: Customer Requirements supersede
Note 2: Manufacturer Recommendations/Requirements supersede
Note 3: VIA in Pad and other design factors shall be considered and evaluated if criteria cannot be met.