60" is probably too short. My nerf bars are 70" and I think sliders need to be about that long. The measurement from fender well to fender well is about 73-74" IIRC. I'm not sure how long the shrockworks and demello sliders are, but I've seen a 4th gen 4runnner or two with 67" trailgear sliders made for the taco and they look too short.
I was going to have some built and we decided on 72" (with the ends angled for tire clearance) or 70" if you're leaving square ends.
edit:
sorry they were 58", which is closer to 60" like you mentioned. Here is the link