You might find the modulation bit useful for this application, which enables modulation of an analog signal by a hardware digital signal. This is available in Type C Switched Cap blocks - refer page 416 of the PSoC1 TRM:
An example usage of the modulation bit for full wave rectifier is below:
You can choose a part such as CY8C27/28/29 that have the maximum number(4) of ASC blocks in a single device.
Thanks & Regards,
The modulation looks very usefull, but since the limit is 4 blocks, it doesn't fit this application.