A Flash Level shifter might work
If you are only needing somewhere around 70MA or so...
Maxim makes a device called the MAX662 @ 70ma, Linear makes the LT1109-12 @ 60ma or if you need just a bit more current, the MAX734 @ 120ma might do.
These are all high frequency step-up level shifters (like those MAX232 chips) that require external capacitors to help with the boost.
Being that these are designed for FLASH use, they have two modes... deliver 5 volts in shutdown mode and 12 volts in program mode.
If you need more current than that... I's start looking at DC-DC modules from companies like Vicor.
Pete