Rear brake upgrade brackets

Ok, so I think we all know that you can upgrade to the Cobra vented rear rotor just by changing your mounting brackets for the rear brakes and using the right rotor and pads. Geting these brackets used isn't easy and I've been cruising on ebay to get a pair for my daily driver because bigger and vented rotors work way better then smaller solid rotors and I drive a LOT... plus I'm going to need to toss my stock rotor finally and why not upgrade ? Anyways, I saw this auction on ebay:
http://cgi.ebay.com/ebaymotors/ws/e...e=ADME:B:AAQ:US:1&viewitem=&item=200117101402

and I thought to myself, I wonder if it is safe to bolt on adaptor brackets to the existing hangers ? A lot of the guys in the classic forums are bolting on brackets to adapt the Bullitt/Cobra calipers onto our early spindles, but those brakets are very beefy and designed by someone who knows what they are doing. You guys think these are safe or do you think the stock brakets would be a safer bet ? These are convienent because you don't need to pull the axle to upgrade but I don't know if the stock mounting flange can take the extra force that will be applied ?

Anyways, I email him and asked if he would sell just the brackets but the guy wants $150. I was expecting somewhere between 50-90 bux, 150 is a bit much. I figre it just looks like a piece of cold rolled steel that has been powder coated, how hard could that be to fab ? Any comments on making a bracket like this yourself ?