I was also going to post the Control Tech bars. I DO have them and there a few things to note. Since it is an internal compression (like an old quill stem) you need to REALLY TIGHTEN it. Otherwise, yeah they slip. They also only fit bars with certain internal diameters, so if yours have a thicker tube wall, probably wont work.
Having said that, the only bikes I would use them on would be mellow riding. Like an urban/city bike. Which was my intention, the bars I mounted them on are too "narrow" for my MTB, but I could see using them on something else.
So another vote for get a new handlebar.