Regulators are built with single purpose in mind and are tailored to the specific application. There are no microcontrolled switch mode controller (this is what I think of when people refer to "regulators") that I know of. They all have analog and some digital circuits internally like op amps, bipolar or FET's, oscillators, comparators, flip flops etc.
I have not seen a driver chip with an onboard microprocessor, certainly not one that is user-accessible. Most small microcontrollers make pretty good switching mode controllers, but the expense of designing them in and writing the software limits their use.
On the other hand, if the OP was asking "Can a microprocessor control a switching mode chip?", the answer is yes. Low end chips usually have a voltage input as feedback to control the current. Some chips also have a PWM input; I think I recall a few that have MODE inputs (hi/lo). Obviously, a microprocessor (really microcontroller) could interface with these. I do not know if Surefire or any other commercial lights do this. A good example of this type of thing is the convertor that drives the backlight in a cell phone.
To try to drag this back on topic to atone, several of Surefire's lights are advertised as
"microprocessor controlled"; it's very unlikely you could tweak the processor to get more output (but you might be able to change sense resistors, etc and get more light at the expense of reliability/life).