Here’s a pic of the trees I got this past January.
In particular, the above post shows how the roots from Grow Organic are much larger than those from Bay Laurel, even though the trunk calipers are similar (both are pretty large, ~5/8 to 3/4"). They are also a bit cheaper.
Chinese Red Date nursery also has very impressive root systems, with slightly thinner trunks. But, if you don’t buy the Amerizao (new varieties which are more expensive), they are probably the most cost-effective option, especially when you consider what nice trees they send. I placed a larger order with them this year, though they are now sold out of many of the new varieties.