Digital BW, The Print

Curious:

What is the word about Variable Tone inksets for the Epson 4000?
I'm wondering also if MIS (or others) have plans/intentions to 
create All-Black inks for the 4000, or is this even necessary?

I'm using the 1280 with a CIS system using MIS Full Spectrum.  I'm 
mostly interested in the 4000 just for the 16x20" capabilities.  So, 
finally, will the 4000 allow one to make Hiqh-Quality, All Black Ink 
prints and color prints without swapping ink tanks?

Thanks!
Chris