Digital BW, The Print

Perhaps someone has some suggestions for my question:

I have been printing with an Epson 7000, piezo/bw inks, and the Cone 
RIP. I'm very pleased with the results but not with the cost of the 
Cone inks. Has anyone found a subsitute inkset that will closely match 
this combination? Unfortunately, MIS has not yet come out with an 
inkset for 6 color printers that match the characteristics of piezo 
inks.

Many thanks,
Stan