As you point out, it *can* be done with 0603 resistors at the top of the input attenuators, however for the O.P's eight channels, that's still a minimum of eight individual resistors and around 37 mm2 of board area even closely packed, before you even consider the area and parts count required for the lower resistors (possibly in tiny arrays of four as the lower resistors in a clamped divider don't have to withstand severe transients), filter capacitors and any input clamping required.
As the O.P. was concerned about the space and assembly work required and was looking for a single chip solution, I doubt they are going to be happy with our suggestions.