A 30 volt voltage span from a 24 volt input.
No. Definitively you are not going to get it with a purely linear regulator. You do require switchmode regulators.
There are some of options:
1- Two regulators, a buck and an inverting regulator fed each from +24 volt. No transformers, only two inductors.
2- A pushpull converter. This would be my preferred for higher power, but you require an output transformer with both primary and secondary center taps and two inductors.
3- Because the output power is low, a flyback converter would also work, but you still require a transformer with two secondaries. But no inductors.