Copyright reasons is why this'll never happen. Many spriters contributed to the mod over the years, half not on the team, and handing it off even for a temporary time would be in violation of those copyrights.
The sprites are wrote out in permission to the AvalonMod team, which consists of a very few selection of members together. Violate that, and you'll not be able to use anything.
Just know that items and NPCs are being coded by the day. Blah may not be doing it recently, but I have the team working on it.