I agree that you need no less than a 18' trailer.  I would get slide in ramps versus a gate or fold up ramps because you may have issues with the Back Hoe.  Also, trailer height make a big difference in loading.  I back my tractor on the trailer because it balances better.  Many with BH's complain that they drag when loading so I would get a low boy trailer.
As also mentioned a trailer with 5,200# axles is the way to go.  A trailer with them that is 18' to 20' long is going to weight about 2,500# empty.  This weight is subtracted from the GVWR so a 10,400# trailer, commonly called a 10K trailer, will have a usable load of 8,000#.  The same trailer with 3,500# axles, commonly called a 7K trailer, will have a usable load of about 4,800#.
Chris