On the topic itself, I would say
(with little suprise) that the easiest way to achieve one's dream (for a dream deck) is to build your own deck. It takes a lot less than one might think - and it comes with the added benefit of "knowing" it is the best for the person who builds it.
I know it stopped me from looking at other turntables once I had mine done.
On the topic of speed control and accuracy, I would not presume to know what
@G T Audio meant specifically (ability to correct speeds or automatic speed adjusments), but I would say that it is very cheap nowadays to build very precise automated speed control facilities in a modern deck. These have the ability to function without any user interaction, and compensate for temperature and humidity changes of the environment, level of bearing run in, cartridge drag and even belt stretch.
If aftermarket control packs for almost any belt driven turntable could retail (with markup) for less than $700 (Phoenix Engineering), I fail to see why manufacturers of high price decks would have any trouble adding those facilities, even as an option...
...unless inaccurate speed is part of the deck's design.