You could, of course, have a new rim and new spokes relaced to your current hub.

Frewheel-type hubs and complete wheels are still available but are considered obsolete so you won't find them everywhere. Try an older, well established bike shop. They might have one still in stock they would be happy to sell at an attractive price.

6-speed and 7-speed hubs are the same overall width (126 mm OLD) so any 7-speed freehub based wheel will fit your frame and 7-speed cassettes are still readily available to fit modern hubs. Assuming your shifters are friction, they will work with any 7-speed cassette.