Hi all,
here's an interesting article: "Generating an Adjustable Bias Voltage Beyond the Supply Rails". It is not regulated and provides minimal
output current but can be a starting idea.

http://www.chipcenter.com/eexpert/s...ix006.html


A note about linear regulators: these need a few miliamps flowing to
load to work properly; if not, the output voltage can be as high as the input voltage. So take care if your device eats only microamps.

Txip.