Here is an updated list.  
I recently went to the local coin store in my area to buy some more 2007 american eagles for overstrikes.  They usually have at least a few tubes of most years, and still sell them at $4 over spot.  Unfortunately they told me that 2007 is a hard year to get in nice condition for some reason.  I was able to buy 15 nice ones without any dings or gouges that will work well for overstrikes.  I looked into ampex but they are quite a bit more expensive, and there is a risk of getting some that are dinged or scratched.  We were getting very close to a total of 40 silver eagle overstrikes on the list, which seems like it would be more than I could get a hold of without accruing quite a bit of shipping cost and higher prices.  For now, unless I can figure something else out, there will be a limit of 1-2007 eagle overstrike per member.  I still have to find a few more for our current order, but it should work out.