Delay lines are common in audio processing (echo, flaging etc).
I wonder if the techniques could be pushed to this frequency...
Bucket Brigade delay lines should result in a simple circuit (output would be time-quantinised).
A fast A-D converter feeding into a FIFO shift register which feeds a fast D-A (output would be time and magnitude-quantinised).
Both of the above would use a variable clock frequency to achieve the delay required :? .