I've been working on such "rare" slow growers. And I'm currently waiting on a bit of agar to be shipped to me by Mistergreen. My last batch was ruined by crappy transfer technique.
I'm just curious if anyone would be interested. Some of the upsides to these plants for me are that they're much cleaner and much faster growing. The benefits for the buyer is that all they would have to do is pop the plant out, wash away the agar in tank temperature water and stick the plug into the soil and you'll have an instant, extremely dense planting with little to no hassle. Think wabi kusa plugs except with jello instead of clay.