Digital BW, The Print

I am trying to budget for a project that will entail making around 
30,000 unique 8x10 b+w ink jet prints. I need to estimate the number 
of 
cartridges I might need to buy. I have not chosen a printer yet but 
the Epson 4000 is one that is under consideration. Speed is somewhat 
of a factor.

Do any of you know how many 8x10 b+W prints I might get, at a medium 
quality setting like 720 dpi, on photo quality ink-jet paper, for 
each black ink cartridge for the Epson 4000?

Do you have any suggestions for other printers to consider? A decent 
printer that is relatively fast at the settings I described, and for 
which there are continuous inking systems available, would be of 
interest to me. [The Epson 4000 does not seem to have any 3rd party 
continuous inking systems--does it?]. I would consider an A4 printer 
but it would be nice to have the option to print to 13" width.

Thanks,

William