Cliff is a good guy and has a massive selection of varieties. He had a bad spring this year with 2 frosts after the jujube leafed out. I think he lost 137 of ~200 mature jujube trees. I’m not sure what it did to his stock, so you should email him and check to see what he has available. He sells a number of different grades. The small and medium are probably closer in size to the small ones I mentioned earlier. I think “Extra large” is the one you should go for, which could be 1/2" caliper or a bit more. He does use taller boxes though, so I think the tree could be a foot or two taller than JFaE.
But I don’t think I’ve ever gotten a potted one from him. They may be container grown, then have the potting media shaken off, so they can be sent bare-rooted. If this is a key feature for you, I’d suggest asking about it as well.
Yes, I saw some 7 gal jujube which is tempting, though $150 is a bit pricey. But, then I noticed that in the shipping area it says “we cannot ship potted fruit trees as they are too large.”. They have a shipping example for 1 gal, so I think they would send them, but I’m not sure how large they’ll go. I think you’d want at least 2-3 gal.
Bob Wells also sells them in pots. I got a couple decent ones from them a few weeks ago: