Yep- if it's a community tank, then just make sure there's plenty of rock and sand in an area for the paracyps to claim. I have a 40 breeder (48") with ~25 paracyps, a group of breeding J. regani, and a pair of gobies (Eret. cyanostictus). The regani are not full grown, so we'll see if this combo still works next year.
But- assuming you like doing water changes, have sufficient filtration, and don't have overly aggressive tanks mates (good candidates would be altolamps, small julies, mild shellies, or xenos), you could easily house 40+ paracyps. For just grow-out, you could raise 100 or more, for a species breeding tank, start with 20-40 paracyps, some rocks, and let them have at it. I have found it important to keep the water clean and stable for the paracyps to do well. They suffer a bit more if I skip a water change or do a particularly large one.