You can put a whole dang lot, if you have an internal network. For instance, AFAIK the 90.x.x.x and the 10.x.x.x (and a few other) groups of IP addresses are reserved for internal networks, so you could theoretically have a TON.
I would say, though, that if you have less than ten IP-recieving devices, and most of them don't move around, that it might just be easier assigning them manually.
