Check with your buyer to see if they have any issues with a mechanical harvester before you do anything.  I would go with something that uses a deck plate which reduces field loss.  JD 300 picker or IH 234 mounted picker.  234 picker would be cheaper but then you have to have a tractor to mount it on and deal with mounting and removal once per year.  300 picker will be more expensive but short and simple hookup-unhook.  I know many people will tell you not to worry about it but storing inside when not needed will greatly extend the life of any picker.  I've been wanting a JD 237 picker for a long time because there was one down the road years ago bought new from the local dealer.  Before it exited the area it sat out quite a bit causing deterioration to metal and non-metal parts.