PDA/ GPS combo for environmental work in Southeast Asia

I’m looking for a PDA/ GPS combination to run ESRI ArcPAD software and collect environmental data in Southeast Asia. My original search led me to the Airis T620 because it had a built in GPS antenna. Further searching revealed that PDA’s with built in GPS might have shorter battery life. So now I’ve broadened my search to include any PDA with Bluetooth capability, that can be connected to a GPS receiver. The ESRI software requires at least 64 MB of RAM, an ARM-based processor (including Intel StrongARM or XScaleT, Samsung, Texas Instruments OMAP, and Atmel), and Windows Mobile or CE. While our working conditions require a long battery life, and/ or ability to replace battery, as well as a decent screen to display satellite imagery. The GPS has to be able to pickup a signal in Southeast Asia, possibly under a dense canopy. Does anyone know of a PDA that would be useful for this kind of work? Or possibly a forum that would be geared towards these types of inquiries? Thanks a lot, any help would be much appreciated.

[Martin Laverty]

You might want to look at teh ruggedised PDA's we do.

http://www.totalpda.co.uk/Ruggedised-PDA.10033/

They're sirf III receiver so they are the best built in receivers you could get and they meet all your other requirements.