thanks for that info. I sorta thought maybe full host mode would not be reasonable because, the batteries in the readers are small and even a single LED can cut battery life a fair amount, especially if you forget to charge it after a few hours of useing a light were it possible to connect.
So much for that idea...
I do have a portable battery pack that works well with AA batteries (I use it to power my mobile broadband router so an LED should be no problem) and a bit of Velcro so I could work around it that way. And I have bunches of Enellops around here, plus I read some news Sanyo might have a new version of Eneloop with higher capacity and an even slower self-discharge rate.