A common problem in things like large SDI router frames, there are a couple of solutions I have seen in that space.
Your ERNI (Or Wurth, see to do very similar things) press fits with a copper bar bolted to them, works but can be a bit of a pain to assemble.
Solder in busbars, essentially a piece of tin plated copper with pcb pins on a spacing of your choice, also stiffens the board quite nicely which can be a win depending on exactly how ridiculous your stackup is anyway.
A water ject cut copper sheet laid over the high current trace and bolted thru the PCB at intervals, those smt style 'Pem' nuts are nice for this (But do use a disk spring under the screw), and 65A (Assuming you are doing point of load regulation) does not take all that much, a 2mm thick, 10mm wide copper bar will not even get warm.
In any of these remember to deal with the return current the same way! Who me?
I would also remind that fusing the individual card sockets on the backplane is a good idea, those 2mm sockets do sometimes take damage and it is better to blow a fuse on the backplane then take the whole thing down in smoke and fire as the connector burns out!
Regards, Dan.