Thoughts/suggestions on this negative high-ish voltage regulator circuit?

[msat]

I have a high-ish voltage multi-output unregulated power supply (see attached image), that's just a simple transformer + rectifier. I'd like a way to add some variable voltage control, and preferably regulation for both positive and negative rails independently. I intend on it being an external device that just gets patched to it with cables.

Now, I'd be satisfied with simply using an LR8 adjustable high voltage regulator, but they don't have negative rail equivalents. I drew up the attached circuit that uses an LR8 ground referenced to the negative rail (VSS) that controls an emitter follower driving the load - with the regulator's feedback coming from the emitter. I suspect this is a bad circuit, but don't really understand why. Will noise on VSS not get rejected? Would that matter if none of the transformer taps were earth referenced? Is the regulator even being of any use?

Thoughts/tips/suggestions are appreciated!

[msat]

Ok, I'm pretty sure the circuit is not tenable because in order for the input of the regulator to be at a higher potential than the output relative to it's ground reference, the output would have to be more negative than the input, which isn't possible. I need to come up with something else.