RDG were selling them off cheaply, a little while ago, might be worth checking to see if they have any left. I have one and will need to dig it out for dimensions. Might be a day or so before I can locate it.
Do they have to be genuine Myford? A couple of metal plates of the same thickness with some fixing holes in them would work, as thick as you like, to get the lathe at a comfortable height.
Colin, As Michael rightly points out it depends on which riser block you want ? Assuming its the pair to raise the machine up from the bench here is a link to an old ebay sale, now finished but the photo's have a ruler shown so you could probably with some carful proportional estimates arrive at the dimensions needed, hole spacing excepted but this can be taken from your machine — hope this helps a little
edit — PS I would have thought the height was of little importance ? surely you can make them to whatever height suit you ? But I have no knowledge of the ML10 !
Riser blocks have two common purposes, to get the height to a comfortable user position, of great value as you get older, and it makes cleaning up the swarf underneath easier. Thats why you might have to make special ones. We raised the 12 x 24 Atlas up on 40 mm thick aluminium at the headstock end so that "leveling" screw adjustment could be used at the tailstock end. At the museum, we lifted the whole 3/4 ton Smart & Brown model A up with the forklift and put a 45mm thick wood frame under the base to ease my old back.
In the past, I have made riser blocks from RHS and used studs with lots of nuts (Below and inside to secure riser block to bench; within and above to secure the studding to the RHS and then above and below the lathe feet )
This makes adjustments to remove twist from the bed easier.