AVR-Chat

I know just enough about this stuff to be dangerous, so please bear with me if 
my question is laughably misplaced.

I would like a circuit designed for an LED candle. I'll be producing about 100 
of them, possibly many more, more, for my haunted house. Requirements:

- Flickers realistically
- Works off standard 9v batteries (or 6v battery packs if necessary) for at 
least 30 hours
- On-off switch
- Costs no more than $12 (and preferably less) to build total, including 
populated circuit board & LED(s). In my fevered imagination, I hope that the 
Atmel processors have pretty much all you need except for a couple of 
transistors, resistors, and an external switch
- LED doesn't have to be exact candle color (I can supply colored cellophane or 
whatever it it's a white LED)

And ideally but not necessarily:
- Fits without the power source in a candle
- Would have an option to plug many of them into a chandelier and power from a 
single source
- Uses a bright LED
- Has some sort of user adjustability for auto-off for power saving, and/or 
randomness setting, and/or flicker speed

Would love to know if this is even close to doable in my price range, how much 
you'd charge to design it, and where I should go to get it manufactured. Feel 
free to contact me offline or to jeer at me publically.

Thanks!

Tom Campbell