I haven't tried anything like that, but maybe even just using chained logic gates, and switches, you could add nanoseconds or 10's of nanoseconds from using multiple gates. How many steps or how much resolution did you need from 20-200ns ? If money is no concern than there's probably chips just for this stuff.
I've never noticed or measured the time delay out of any filter circuit I've made. That's not true but, not for making a nice, delayed good copy of a signal. But there must be analog ways to do it too.