This first part is just informational and of absolutely no use to you because replacement motor mounts (rubber parts) are not being reproduced by anybody anywhere, not a parts stores, not Mustang specialty stores... nowhere.
If you are looking for the exact/stock Ford motor mount combination (frame/engine) for bolting a 250 into an early mustang without modification. It would be these ones, pulled from a 1969 Mustang 250/3.03.

compared to a stock '67 200 frame and motor mount
I find it interesting how much slop/adjustment is available in them. The passenger side frame bracket has all three holes slotted, the bottom of each frame mount has a long slotted hole. The stock 200 frame mounts have only a slightly enlarged hole for the motor mount bolt, but it isn't a slot.
And now that we've covered the useless info.. how about something useful..
For the price of covering shipping I will send you one of my prototype motor mount sets. This goes for either one of you schaferstephen or rocklord.
Understand that you'd be guinea pigs and that I'd expect feed back, I'd appreciate any pictures taken of final assembly and unexpected issues encountered. I only have 3 sets of these right now, and I supposedly have a loaner mustang coming to me after the 4th of July. It is a 1966 200/manual, car that has no motor or transmission in it currently. I have a 200 and a 250 sitting on my shop floor so I will be keeping a set to do my own test fittings.
You can read about the creation of these right here on FordSix at this thread:
Small Six Motor Mount Dimensions
They are designed to be used with the common 170/200 frame side mounts.
I will provide all the brackets and the tubing tack welded in place and a piece of 1/2 OD 3" long steel tubing (fits a 3/8" bolt nicely with its ID). The 1/2" tubing is to be used inside the shackle bushings as a spacer to prevent you from crushing the ends of the bushings.
You will need to perform final welding, because I shouldn't be allowed to weld, seriously, look at this ugliness.

You will have to provide your own set of shackle bushings. Any '65-70 Mustang shackle should work, I used 1968 Mustang bushings.
For a 'production' set, that is all that would be required to have them be usable. However since the ones I am offering are prototypes.. lets just say I didn't get it perfect the first time around. On the sets I am offering you will have to cut or grind off part of the mushroom head on the shackle bushings.
This is the area of concern.
A stock shackle bushing, you can see the molding line between the flat part and where it transitions to the dome/mushroom part.

You would have to cut/grind it off roughly here.

The reason for the bushing grinding is because when I built my first press dies, I measured correctly but welded them together incorrectly. And then neglected to verify until AFTER I had bent a set.

Its not the end of the world, the ID of the larger brackets is supposed to be 3.5" (the length of a stock unmodified shackle bushing) however I bent them at 3". So each shackle bushing needs 1/4" of material taken off the end

opsie:
And one last annoyance. The smaller of the two brackets that holds the tubing for the bushing has a bolt hole that attaches the mount to the frame bracket. The only way to get anything through that hole on the prototypes is to hold a nut on the top and thread a bolt in from the bottom. I've had that hole moved father away from the tube on 'production' ones so the bolt can be dropped in from the top..
If either of you are interested, shoot me a PM and we can make arrangements.
-ron