There's really nothing radical about it. It's rather reversible. The motor is just connected to one of the boards via a 12-pin connector and why do you even need to take the boards out of the stock chassis? Just leave them in there and you will have three pieces of hardware acting as a record player: the power supply, stock chassis, new plinth with motor. I know, they take up space. But making plinth just for the motor will be much easier, just cut a 6" hole on the plinth and mount the motor in it. That's it. As far as length is concern, I don't see extending few feet of cable would be a problem as long as the voltages remain the same. In fact the MK3 did exactly that by removing majority of the electronics onto the power supply chassis. Kaneta in Japan has been doing this type of mod for years. In fact I believe almost ALL direct drive can be benefited from this. I had over 30 direct drive turntables of various cost, and after examining almost all can be improved by removing the motor out of the stock chassis or plinth - most of them are either made of particle board or plastic or thin cast aluminum. They are basically a hollow box with fancy wood veneer. The Monaco turntable takes the same approach by having the electronics separately and have the motor mounted on something really solid. It's funny with the revival of idler drive turntables, all the audiophiles talk about regarding these vintage gems is the plinth. But when it comes to direct drive, it's a different story. Most people only cling on to just a few models like the SP10 or SP15 due their manual operation. And if you want the automatic operation from some turntables then, obviously, they are not good choices.
Currently, I am using the motor from a Pioneer PL-L1000 with a broken linear tracking arm so I decided to use just the motor and drive electronics. Pioneer motor and bearing is first grade with their excellent Stable Hanging Rotor (SHR)inverted bearing that is similarly employed in their flagship P-3 turntable. I installed the motor on a thick butcher block with cantilevered armboard and placed the electronics in a separate chassis. And it sounds excellent. In stock form, the motor is bolted to the bottom suspended plated that is made of wobbly plastic!! What an eyesore! I also have another unit with such mod so sometimes I tape drive one another. It's fun!
Of course not all DD turntables are good candidates. I would avoid doing this with certain brands such as Sony and Denon because they use a magnetic head to pick up signal from the platter's rim for the servo system. It's do-able but it's just more hassle. Some models have the pcb attached to the motor like the Technics SL-1200mk2, so that's not a good one. But the SL-1300/1400/1500mk2 series are excellent choices for such mod due to their detachable motor and nice dynamically balanced platter, which render them a notch above the boring SL-1200 - essentially an SL1500mk2 is an SP15 minus the 78rpm speed. But their tonearm is not as good so here's the chance to try something different.
I have a broken spare SP10, parts unit, that has speed issue so I am thinking of taking the motor and platter out and install on a new plinth and let it be driven by another SP10 acting as tape drive. As much as I like direct-drive I am also very fond of tape-drive with another turntable. I've been using these dual turntable set ups for a year now and I am really liking it.