John. Greetings.. What specific brands and models are you looking for? Our B stock changes rapidly.We spray our hands liberally with stickum and if any manufacturers lob up any B stock, which itself is quite limited in quantity and quite variable in availabilty, we try to snatch them up for AV Science. Any advertisement for a B stock unit should clearly state B stock and it should not be dependent for the buyer to have to pick that up from a -B on the model number. For example a B at the end of a model number often means "black".
Warranties for B stock may differ from normal stock warranties. For example, JVC has the same warranty for both while Sony ES is three years for normal and only 90 days for B stock. So I always recommend a direct from Sony extended warranty for any B stock Sony projector. Hope this info helps.