Probably the easiest way would be to use something like the cad-digger plans, beef up the size and weight, then adapt the mounts to fit as needed. You could use some of the basic dimensions and change the front to mount whatever you need it to fit.
I don't know where an actual bobcat attachment is, so I can't get actual pix of factory made unit.

"A machine you build yourself is a vote for a different way of life. There are things you have to earn with your hands."