Jim,
Without knowing any more about this application (frequency, power supply availability, cost or size restraints, stability of output, duty cycle or type of waveform), I was thinking that a low pass filter and an op-amp that is unity gain stable in the follower configuration would probably be enough. TI has a large selection of Op-Amps, I'm sure there is at least one that could meet the customer's needs, if this is a satisfactory enough solution.
I attached a TINA simulation I did of this configuration.
(Please visit the site to view this file)
Jason Bridgmon