How much more jounce travel is left in the rear suspension? I ask now because if there is enough left to need C-notches in the frame the panhard bar is going to contact the top of the housing pretty quickly. You do need to move it but not just for floor clearance. Move it down and rearward. Put it behind the housing, keep it straight at nominal ride height to reduce side to side tramp during suspension travel.
As far as the radius rods go just build a tunnel over each one like Keith mentioned. I had to build a couple for my Astro project to the clear the upper link bars. I rolled some 18ga sheet metal and spot welded them into the floor. And remember, the front of the bar is fixed so it will move very little in relationship to the floor so you don't have to go "all the way to the front seat" to have clearance to the bar.
Mark