yeah, i've seen those bullet pipes at my headshop. and yes, if you're looking for portability and stashability, you probably shouldn't get glass. a bullet pipe or actually my local headshop has mini stone pipes that are extremely small...i love stone pipes, so i would recommend one of those.

edit: i found this pic of a bullet pipe online...but the ones at my local headshop are about half the length of the one in this pic