Here's another take on the PCB for the extra LPF switching relays. As per my previous suggestion, fitting the PCB to the edge of the uBITX main board by seam soldering them together.
This preserves a very good ground return.

The PCB uses HK4100F-12v relays which are cheap on ebay. 'Should' be ok for qrp levels.? They are a SPDT type relay and mounted on the back of PCB shown. They are similar in height to existing LPF relays.

Similar track cutting mods as Gordan has stated, except a variation in the 400nH LPF section so all inputs are on the egde of the uBITX board.? The PA output feeds the board at the end nearest the heatsinks. ie a very short coax cable is required.? Four short (5mm) wire links from the edns of the LPF sections to this board. You can see the 4 holes down the left side which is actually rotated left 90deg when fitted.

The transistor relay driver stages have been duplicated, but can also be not fitted, as pads are provided for this also. All relay coils are bypassed both sides and along the tracks too.? I might add some ferrite beads also.

The PCB is approx 36 x 50mm in size.

<LPF_EXTRA_RELAYS_DRAFT pcb_v3.jpg>