[PStamler]

Eight-in is, as you noted, one of the standard sizes. Who are those 8-input interfaces for? Mostly people in smaller bands -- not everyone has a horn section or multiple backing vocalists. Count 4 inputs for the drumkit, one for the bass, one for keyboard and two for guitars; for most bands that would let you track most of your instruments in a single pass, then do vocals one at a time.

Along with the other recommendations from this group, you might look at products from Presonus.

Peace,
Paul