I don’t think such a list belongs on the official website for the reasons explained here. However, if you’re willing to commit to maintaining such a list indefinitely here on the forum, we certainly link to your list from the official website.
I think that would be Purism. I’m not aware of any others.
It would probably not be terribly useful to have a list with only one entry, given that we already have the “just works” list.
In fact, now that I think about it, the proposed list probably shouldn’t exist now that we have the “just works” list. After all, any shady outfit can start selling laptops “preinstalled with Qubes OS” even if those laptops are completely unsuitable for Qubes. Any good laptops that come with Qubes preinstalled will already be on the “just works” list, so this new proposed list would just end up being a (less reliable) subset of the “just works” list.