I'm looking into the same thing on 16 channel mixers and this is what I think I know:
As Diragor says,
the Alesis Studio 32 has direct outs for each of the 16 channel inputs. So does the Allen and Heath MixWiz 16:FX (see recent +++ post/review below) and
the Soundcraft Spirit Folio FX-16. The outputs on the Spirit Folio are selectable pre- or post-fader.
The Mackie 1604 VLZ has only 8 direct outs for some reason.
My choice (on paper, er.. computer screen) is the Spirit - to get a sweet EQ, longfaders, lownoise, quality mixer with flexible ins and outs, 4 buss, subgroups, and built in Lexicon effects. Problem is I can't affort it (>$900) and I have not been able to find anyone who can give me a hands-on review of it.
So...I'll probably try to pick up a used Alesis 32. I see them available used in the <$600 range and the reviews I hear are all positive. I've had my hands on one of these and it seems adequate for my needs, if a bit cramped. I'd just have to also pick up a decent outboard effects unit, which is probably a good idea anyhow...Except now I'm back up to the $900? Oh well, I don't think I can go too far wrong with either one.
Anybody out there with experience on the Spirit Folio FX-16?
My $.02.
DickD