I don't have a source, but I read somewhere that mail-order skirret, or skirret from seeds, is likely to have a woody root core. There is an improved skirret without a woody root core, and so far the only way to get it is to know someone who is growing it.
it is something I have been looking to try as well, maybe if someone is growing it they would be willing to sell some roots?? or crowns?? they should fit into one of the smaller USPS boxes fairly easily to ship.
Bloom where you are planted.
I ordered mine from here: <http://perennialpleasures.net/>, and they were lovely to work with. Had some groundnut, too! Highly recommended. I haven't tasted my skirret yet, but I hope to try it this fall.