DIYbanter - How standardized are metal lathes?

Hi,

How standardized are metal lathes? Admittedly the one machine
shop I use has 4 identical lathes, so I have little sampling.

For my rose engine, I am interested in making an existing lathe
the foundation. If other people wanted to use it, it would be very
cool if the same parts matched easily to any machine. But I just have
no idea if many lathes have similar bed cross-sections, the most
important thing.

For the rose engine I could use a rocking headstock (in which
case, I hope that the rails of all beds are spaced as far apart so the
same headstock is perfectly transferable). I would machine a new
headstock that would simply be plopped on in front of the existing
headstock and come with its own hand-crank.
Or, I know that our ltahes have a whole bored all the way through
the headstock, so parts can pass infinitely deep through the jaws. Do
all lathes have this bore, and is it of the same diameter,
standardized? I could mount the mechanism off the back of the
headstock, which has been been done before, albeit in 1890.

As importantly as a standardized bed, are the t-slots in the
carriages, by which the toolposts are held, standardized enough at
least in width of the slot that I could make an addition that would
easily bolt into the majority of metal lathe carriages?

Or with all the makes and models and manufacturers, and over
decades (I'm sure that numerous lathes a century old are still in use),
is it a hopeless mess, each lathe with its own slightly different bed,
carriage t-slot, and headstock design, and I should give up now on
every designing a universal accessory to metal lathes that relies on
being compatible in the aforementioned manners? Will it simply have to
be built to match the specific lathe in question, and redesigned and
rebuilt if to be used for another, and again for a 3rd metal lathe?

thanks!
-Bernard Arnest