There was a recipe for pretzels in BYO a few months ago. I've made them a few times, worked out quite well. I used baking soda instead of lye, but they still tasted like pretzels.
I think you can keep them for years,because after a couple of years they still taste the same <!-- s:P --><img src="{SMILIES_PATH}/icon_razz.gif" alt="" title="Razz" /><!-- s:P -->