I just went through this exact thing. Currently I am installing late model Cryo'd birfs with short Aisin hubs. I have all the parts for it and just waiting for a nice day to change out the parts. I will be getting rid of my long birfs and long body Warn hubs when I am done. In case you are interested.
Long birfs 76-78 will not work with short body Aisin hubs as you can see. Long body Aisin hubs (pig hubs) are out there you just have to find them. One solution that you might be interested in that I saw on MUD, was to cut 10mm off of your long bifs and have a new C ring groove machined in.