If you've done a power supply before go with what you know. Design a new power supply, only one that has features that your previously designed one's didn't have, perhaps a constant current or/and power mode. Add frequency generator type features to the power supply so you can modulate it with different signals, perhaps for the purpose of introducing intentional transients to a circuit to see the devices responds. You could intentionally allow the main VCC voltage to be modulated very shallowly by an audio source to see how it responds to cross talk, skies the limit.
Go with what you know, but do something new too, and more importantly something that interests you as well.