if linux is not a hard requirement, then the Symbol SPT 1800 looks to be exactly what you need. i think there are other manufacturers in the same product space, with choices of pocketpc models, too.

don't underestimate the importance of a ruggedized unit for use in a warehouse environment. something like a tungsten c/w/e is not built to handle a drop on a concrete floor, and it wouldn't last very long in the hands of a typical warehouse worker.

disclaimer: my dad is a reseller/integrator of symbol products (and some competing lines), and his firm works with applications like this all the time. i've even written some custom code for some of their clients who lacked in-house development.

good luck,
--dan.