Problem with active boost is this....................Unless you have noisless pickup like Lace Sensors, or Fender Vintage Noiselss etc, you'll end up boosting the noise your pickups make as well. Sounds strange I know, but thats why the Clapton Strats use the above mentioned pickups. There noise floor is low enough to not be affected by the boost. It all comes down to signal to noise ratio, and your average single coils just wont be upto the task.
Trust me Ive tried it.
If you still want to press on, give these a go :-
http://www.generalguitargadgets.com/asb.html
Use the Guitar Cavity version. Ive made this and hade good results with Lace sensors.
http://www.generalguitargadgets.com/
Here are more DIY effect type projects.
Good luck!!!!