Years back we used different types of handlebars for our cable machine when weight training. Also used different handlebars to angle our grips when doing pullups/chinups. But as the weight increased it became evident that something was gonna give! I wouldn't advise doing it for most any weight training!
A lot of the FreakBikers have used straight handlebars for seat posts on their Pixie racers. They usually are bent after a few races.
Cut up bars and made plenty ofcrazy new handlebars over the years.
We make many of our Great Lakes FreakBike Banquet trophies using handlebars and other bike parts.
I cut the straight part of bars and use them as sleeves for the tubes of many of my frame builds.