Where can I find these? I've been looking all over.
PDA, found at www.fractionalplates.com, will custom make any type of trap bar with your choice of grip thickness all the way up to 3". They tend to be very pricey.
The poor man's solution would be to buy any old trap bar and duck tape some PVC pipe around it, or something similar. If you want to go this route, the cheapest trap bar I've found is sold by Jesup Gym. They sell their stuff online through e-bay. Just type "trap bar" in the e-bay search window and you will find it. The cost is $120 and shipping is included in that price.