Gordon has been testing out his mult-relay single ended board. The concept here is that the existing LPFs and relays are reconfigured on the µBITx main board and the ends of the LPFs are connected to a new daughter board attached behind the LPFs and relays to provide for greater RF separation between LPFs.
And this photo shows the cuts made to the top of the board:
And showing the connections to the add-in board
And a different view showing the wiring to the main board:
And the relay power on connections:
The results seem promising.
A separate board with all LPFs mounted on the external board (e.g. this one) would not be much larger overall and would require fewer connections to the main board.
A document with all the explanations of how to create this modification, including photos of traces to cut can be found here.