I'm not going to make some boards with pins and some without. That basically makes my solderless solution only "solderless-if-you-take-a-shipping-risk". It doesn't make very good business sense to take the primary feature of my product and associate it with "if you want to chance it"
Obviously I'm better off focusing on a solution to the problem.
The nylon spacers won't work as you say because the ring of the spacer would (with enough force) push into the foam but the hole of the spacer obviously would not... so the foam where the hole was, will still be there... and will still compress the pins. So unless I could find little "cups" instead of spacers... that's a no go. But thanks for the suggestion anyway!
After exploring the various options and playing around with the shipping calculators... I think the best option is also the simplest... use boxes and bubble wrap. It increases the cost of shipping for the customer, but not by as much as I figured it would. In most cases, it takes the cost of ground shipping from about $6 to about $8 and air shipping only moves from about $8 to $9. The more expensive options (XpressPost, Priority) go from expensive to super expensive, but I don't think anyone would ever choose those anyway. My biggest problem with this solution is the EXTREME over packaging
I'm an environmentalist, more often than not, and seeing my tiny board in this big biox... it just looks wasteful. On the other hand, I have these boxes here already and I have a bunch of recycled bubble wrap.
So problem solved