What chip are you using? Anecdotal evidence, but...I'm using LM5122 (75mV over-current threshold) in an application with a peak current of about 25A. I'm using a normal 2512 sense resistor, and an 2R-C filter, as per the datasheet recommendation. The distance between the sense resistor and the chip is around 10mm. I've done pretty extensive testing, and no weird glitching, unexpected shut-downs, instability, etc. If not using a true kelvin package sense resistor, you can still get adequate sensing by routing the traces direct to the pads. Assuming normal high-side current sense method, make sure to route the + and - current-sense traces as close to each other as possible. Route them over a ground-plane, preferably part of the ground plane not carrying heavy current.