Single AA cell LED booster circuit

Hi there!
I'am looking for a circuit that can boost the voltage of one AA battery(in the range of 0.8-1.5V) to 3.5V for white LEDs with a current of 60-100mA. The circuit should has a good efficiency of about 80-90 %. I already looked for a circuit but i didn't really find something useful.
Have you got some ideas ?
Thanks for the answers!

I've used the Zetex ZXSC310 in the past when I needed to drive a white LED from a single nicad AA. I don't think I've seen good data on how much current it will deliver.. it might be close to 60mA. It's not a well controlled boost converter.. but it is fairly simple and small.
I've use the ZXSC310 in a few of my bike lights.

Zetex was purchased by Diodes Inc, and their web site has a reasonably good selection of boost converters that can operate on 0.8V to 0.9V.
http://www.diodes.com/catalog/Low_Voltage_DC-DC_LED_Drivers_70/

They sell a part marked PAM2805 which looks ideal, and in fact appears to be designed for a flashlight. Unfortunately, I was never able to find any place that would sell it in small quantities.

Their ZXLD381 boost converter looks like a contender.. the datasheet suggests that it can deliver 70mA to 80mA.
http://www.diodes.com/_files/datasheets/ZXLD381.pdf

The efficiency for these parts might hit 80%, depending on the load and input voltage. I think there are problems making good low-resistance MOSFETs that will operate at such low voltages, or maybe it's just hard to do at low cost in small packages??

Thank you very much for quick answering.
I think i'll use ZXSC310 because i can get it very cheap on ebay or somewhere else.
But i have one question: is the Stdn pin just there to switch the ic on or to standby-mode or can it be also used to be control the output voltage (LED brightness)?
This would be very handy because then i could use a microcontroller to dimm the LED and get better efficiency.

the STDN pin is intended for shutting down the converter, and that's how I use it.

Could you try to pwm it?? maybe... you'd have to check the datasheet to see how fast it responds. My guess is that it's not suitable for it, or else the datasheet would talk about it.

Okay, i'll order some of the ZXSC310 and will try it. But when it does not work to pwm it, the chip still seems to very good for that what i want to do.

The nanjg 110 will do the job and has a sense resistor that can be changed to set max current. It can also be found in some cheap AA lights in 15mm size on EBay. A stack using an Attiny controlled fet driver as well can provide it with modes.