Sorry, couldn't find any mention of the MTOW, what's probably meant with "60t".
For me, it looks like the Do 31/131 without additional lift engines. A "60t" VSTOL
aircraft would have needed some more power, I think ( 60t is about the weight of
a loaded Hercules) !
From external appearance, the largest Dornier VSTOL project I could find is shown
below, unfortunately without designation and again I don't even know the source, sorry ...