The majority of our paper is Crane's Lettra, and we love it because it's soft (so takes the impression nicely), strong, and made specifically for letterpress printing. But what's also great about it is that it's made in the USA and:
And our colored envelopes:
The polymer for our modern printing plates is from Japan; a company in New York turns them into printing plates for our use.
Thought you might be interested!
P.S. Don't forget: save 15% off your order of $50 or more with coupon code DAD15 (code expires on 5.31.14) when ordering from shopinviting.com