About the closest thing I have ever seen, that doesn't really require any programming experience was something called Browser Bob, which allowed you to make custom IE/Trident based browsers. Artistic talent was necessary for best results. It wasn't suitable for an open source project, but it sure was fun and the results were pretty cool.
Unfortunately, it was pretty expensive for the Pro version and it seems to be abandonware now, so I am not sure if you can still buy it, which means you would be stuck with the limitations of the trial version and after 30 days you wouldn't even be able to use it any more.
You might still be able to get your hands on the older v2.1 freeware from somewhere though.