Nice job. That looks like some really well done work that you have right there. I've been increasingly interested about bldc controllers after seeing a skateboard fitted with a 2kw motor and batteries. There's nothing so special there - though the thing that caught my attention was that it has regenerative braking. A controller that would do that would make so much difference for power-generation and transport applications.
That article immediately prompted me to remember the flea(http://www.flyelectric.ukgateway.net/avr_ff_timer.htm
) - basically firmware that could be flashed to stock Turnigy Plush 6A controllers to include a free flight timer. A feature that will only enable/run the motor for a specified time. A few days of searching later, and I found the page again. Looking over it, it's meant for an ATMega8 and is written in ASM. The important point being that the Plush 6A is designed for sensorless motors - i.e plane motors, rather than car motors, which are typically sensor based. The code contained within that project demonstrates the software required for this motor type. Obviously, this could be re-done using FETs that were rated for more current, or with a front-end that was designed for a higher voltage.
Current and temperature measuring would certainly help to make the shield more idiot proof. Position encoding is sure to be of use to some too - though that may be more effectively realized by way of an optical encoder applied to the output shaft. Not too sure what the controller itself would want to do with such information.
But, I digress. I'd think that the ability to control sensor-less motors would provide the most utility to the largest number of people. It would, for example allow simple cd-rom motor controlling. Yeah, I know they have hall-effect sensors in em - but they're a recovery item from old drives. They would be a $0 option before spending $5 or $6 on a 100 watt one designed for RC.
Also, my math is a little rusty. How many rpm will 30khz allow? Is it divide by 2 or divide by 3 (1.5 * 2) for a 3 pole motor.
So, to sum up, I see great utility in being able to handle both sensored and sensorless motors, as well as being able to handle Delta and Wye terminated windings. (I forget if there's more to it than just the current rating. I think one type runs into synch problems more easily than the other - this may be a simple product of motor speed)
Also, something that seems related, only if loosely, is the DeviationTx project (http://www.deviationtx.com/
) It allows firmware to be changed inside transmitters so that they can be switched between DSM2/DSMX, Walkera, Turnigy, FlySky, 9Eagles, etc, etc communication protocols.