Internal game saving mod

Is there any mod out there that you could save to an internal memory bank inside of the 64 instead of having a memory card in the controller? Possibly a mod that could take the board out of a memory card and connect it somehow to the N64 internals? The reason for this is that there are some nice wireless controllers that can be used on the N64. And I would hate to not be able to save due to this. Thanks for any help.