I understand the concern. However, I was asking whether you know where the Dog Mountain mugs are made. Even if the ceramic mugs are made in a country that's less lead-conscious than the Unites States, the finish may be done in Vermont at Dog Mountain. They would be required to meet FDA approval for lead content as well as EPA approval for the amount of lead that can leach from the mug. I don't know this particular operation except for what I've seen on their web site (what charming artwork!) but they sound like the type of operation that would be fairly safety- and health-conscious.
Here are links to a few of the many web sites I found discussing the likelihood of lead in a glaze, where you're likely to find it, and factors that affect its likelihood of leaching into your food:
Lakeside Pottery's article, "Lead in Ceramics and Pottery - Consumer Issues", discusses the issues for the consumer as well as the potter. Note their assertion that if the glaze is fired properly the lead should be bound and not leachable. I ran across that assertion more than once, at different sites that did not seem to be quoting each other.
This peer-reviewed article from the University of California's Agriculture Department, "Lead Leaching in Ceramics Difficult to Predict", may be enough to convince you that you'll only want to use clear glass dishes forevermore. However, they also have tips on the types, styles and sources of new ceramic dishware that are most likely to be safe, and they give information on how you can test for lead. Test kits are inexpensive and readily available, by the way, but I understand that you'd rather purchase without having to test.
The Australian government's Department of the Environment has posted this fact sheet titled "Lead alert facts: Lead in ceramics" that you may also find useful.
My sense is that new ceramic mugs made in this country are likely to be safe enough to purchase without worry. Back in 2004 I tested several of my glazed pots for lead and satisfied myself that they were safe to use. However, as the saying goes, Your Mileage May Vary.