I did mine a long time ago on my truck, welded them to the frame, although I guess you could build it to bolt on, but it will be a lot more work to do it correctly.
You'll really need to gusset the frame for every bolt you use, unless you don't expect to really use them to their fullest extent. Here's some photos of when I built mine back in '05:
The stock I used for the sliders. Welded the ends, thinking I'd use them for air tanks for the onboard air compressor. Decided not to do that:
Three brackets per side made so that it disperses the load of a full hit on the sliders:
Measuring off the body of my truck so that its not too far out, but still enough to keep the body from being hit if I slide into a tree or rock. Approximately 1 inch off the body using magnets I had laying around:
Just a photo of the weld joint after I painted it with non-slip paint. Guess I was too lazy to grind them down and make it all pretty:
Finished sliders (wow! I was still IFS up front! LOL!):
Overall, I'm super happy with them! They're still on the truck, and have been through some SERIOUS bashing! And, they also protect against *******s in parking lots too! Had a guy who flung his door open on an old chevy car (don't recall what it was now, maybe a monte carlo or something?). He flung it open so hard that I felt my truck move (I was sitting inside my truck when it happened). He got out, all pissed off looking, looked at his door's edge which was now completely bent 90º where it hit the slider, looked at me as I started to laugh, got in his car and sped away!
Bet he never slammed his door into another car again!
Anyways, I have the dxf files for the sliders I made, used a cnc plasma cutter for all the plates. You could just send them to one of those online cnc shops and they'd be able to cut them all out for you.