When I first started trying to swap a 1217 around I thought that the 1240, 1250 and the 1260 all used the same sub-frame. When you look at the parts books it first looks like that but then you notice that there are two frame assemblies that are listed for the 1240/1260 tractors with different frame kit numbers. There is a misprint there. If you look at the order codes and shipping bundles you can see what has happened. There are two lengths of frames. The short frame bundle 1017 039 and bundle 1017 036 fits the 1240. The standard frame bundle 1017 035 and 1017 036 fits 1250/1260 tractors. The dealer order code for the 1240 is 5269 723-2 and the order code for the 1250/1260 is 5269 720-8. There was a MF1240 with a 1217 setup on it and we tried to put it on a MF1250. That is how we discovered that the sub-frames were different.
The backhoe without a bucket weights in at 803 pounds. The width of the stabilizers when they are up in transport mode is 6' 3". With the boom locked, it is about 5'3" - 5'6" tall from the bottom of the frame to the top. I don't have the length hoe with the sub-frame. I could measure one that would be pretty close tomorrow if that would help.
I hope this helps some.
I might add that there can't be much difference between the lengths of the frames. The way the front of the frame bolts on, it would be very easy to lengthen it.