A couple of forums have a very rough sketch of the wide push bar with measurements, but I can't see any plans for the narrow one. Having said that, the Smith Bros. site still appears to offer a narrow push bar for $299, which includes shipping to the lower 48.
I'm sure you've probably searched the internet, but I found an interesting discussion about the pros and cons of each type of push bar, and advice on fixing methods, at www.dodgecharger.com. It looks like the steel push bars weigh somewhere between 30 and 45 lbs, and several people expressed an interest in getting push bars made of aluminum if they could get plans. The dodgecharger link above also discusses the best way to paint them.
I never joined CGLFC, but did browse it many times. If there's any information you need from that site, you may be still be able to access it through the Wayback Machine.