I too would love to grow kudzu... however, many places in North America consider it an invasive species and have legislation against it. I know where I live, they've put it on the invasive species list and it's now an offence to import it here. I guess they don't know what a valuable food, fodder and fibre crop it is. If they knew, it might not be the problem it is now.
You'll probably have trouble finding legal sources of seeds for kudzu. You'll have to decide for yourself if you want to source the seeds alternatively. Be careful of doing it publicly, as kudzu has a lot of attention focused on it right now.
Travel around the South around the time of the first fall freeze. Look for patches of just frost-killed kudzu and help yourself to the seedpods. It has such a bad rep that it would be hard to find the seeds for sale, but with a little scouting it isn't hard to find in unattended places.
There are several places in the area where I can collect all the kudzu I want during the season: behind the BigLots, behind the IGA, behind the Walmart, see the pattern here? Anyplace overgrown with kudzu will be some neglected property, and if the kudzu is happy and healthy (not too stressed by the kudzu bug), it will flower and set seeds. They look like pea pods, and the seeds are about the size of a small lentil, 3-6 to a pod.