Hi,
The 4520 has 2 CCP modules so you can get two PWM-outputs, ie two PWM-signals with the same frequency but different dutycycle. The reference to "one, two or four outputs" probably refers to using the ECCP module in half or full bridge mode. Then the PWM signal "comes out" on multiple pins but it's still "the same" signal - basically.

The 2331 also has 2 CCP modules plus the PCPWM-module with 3 PWM generators (the 4331 has 4) so all in all, using the 2331, you can get 5 PWM outputs. Note that the HPWM command does not work for PCPWM module in the 2331, you'll have to configure it "manually".

If you don't need the extended features of the PCPWM module (which, by the sound of it you don't) then perhaps something like the 25K22 might work, it's a lot cheaper then the 2331. There are loads and loads of 18F series parts with 3 or more (E)CCP modules. I'm not entirely sure if the HPWM command supports more than 2 channels though but it's easy enough to configure the registers manually.

/Henrik.