Translating to "below ground" logic levels
This should be fine since you only need 100 &micro;s response.  With 10 k&Omega; output impedence, the 10 &micro;A load will only cause 100 mV of offset, which is well within your spec.

Note that this inverts, so the CPLD output polarity needs to be adjusted accordingly.

Added:

I just noticed that maybe you only want 0 to -3.3V output, not +3.3 to -3.3 V.  You mention 0 to -3.3 first, but then talk about &plusmn;500 mV as being acceptable, so I'm a bit confused.  In any case, here is the 0 to -3.3 V output version.  This one does not invert.