It took me nearly a decade to find starts of Okinawaan SPinach, finally finding it on e-bay. Once you have a start, you'll probably never be out of it because it's a hairless relative of the old houseplant Purple Velvet/Plush Vine. Mine are pretty ratty right now but I'll have starts for those that want some of either/both of the Purple and Green forms(no difference in flavor). They root easy and grow fast. If you don't have a greenhouse, just take a bunch of cuttings in Fall and grow as a houselplant you can nibble on till Spring!
Cheers,
Pat