On the Nexus are a few reskins of the dart gun but thats it. Sadly there are, as far as i know, no Bows or even real Crossbows.
Looks like no one cares about classic weapons.
That http://en.wikipedia.org/wiki/Compound_bow from First Blood: Part 2 would look sooo nice on my evil assassin.

If it just wouldnt be illegal to port animations from Oblivion to Fallout 3...