Digital BW, The Print

I'm a newbie at this so I hope some of the more experienced users 
can guide me in the right direction.

I need to print high-quality BW in at least 16" wide, preferably 
24". Ideally I'd like to have a printer that would do both BW and 
color, but failing that I'd dedicate a printer to BW and have an 
outside lab do the color.

Is the Epson 4000 a viable option for both BW and color? The size is 
on the bottom end of what I'm looking for, but it might do. Or 
should I just forget the color and look for something like a used 
Epson 7000 or 7500 and set it up with BW inks such as MIS or others?

Has anyone had any luck with the Canon W6200 for BW? It produces 
great color with reasonable ink costs, but the BW results I've seen 
so far exhibit metamerism.

Thanks.