The corn head shouldn't be a problem, it appears to me to be a much smaller change than everyone makes it out to be. From what I've seen the biggest change is to the hook on the top part (which I don't think looks very strong, but that's a different story...) instead of the lugs on the old machines. I've been told, and it appears from looking, that the bottom pins and the shafts are the same, so it should be a small modification. As far as the hydraulics, If you have hyd deck plates, it should be easy to convert to the new hookup, just need the one block. Unless Deere is way out in left field, the conversion you will need for a corn head should be really cheap, especially when compared to the combine. And from what I can tell, it's not really an adapter, but a conversion, not like putting a Deere head on an IH or something. The feederhouse does not look that different to me. Personally, I would make it part of the deal, that they have to throw in the parts for the corn head for free (not just add the price in somewhere),or there's no combine sale. I would assume you'd get a hydraflex, because that's where all the difficulty seems to be, dunno if the new machines will be able to use DAM or whatever replaced it.