Try this HP8500A all in one unit. It has seperate ink tanks for the colors.
I have the HP7410 which is basically the same as this but which uses
Tricolor ink cartridges and a Black cartridge. The HP8500A was the replacement
for the HP7410 .. go to your local Staples or Office Depot and have a look at it.
It has Duplex, RJ45, Wireless, FAX, Copy and does front load with 2 trays
Also has Scanner and Auto Doc Feeder