I ran across another place that can seal a spoked rim.
Wheel Works in Garden Grove, Calif can do them from what I read in
this article at motorcyclecruiser.com Finding an America hub could be a problem. I wonder if Triumph will sell you just the hub? Another possibility is using a Thrunderbird fron rim, or maybe just the hub off one if you can get one cheap on ebay.
In this thread Benny says he has a Thunderbird front wheel on his America.
