It's not really any different that regular NAT -- just that you're using RFC6598 space (100.64.0.0/10) instead of RFC1918 space (10.0.0.0/8, 172.16.0.0/12, or 192.168.0.0/16).
So your setup will end up being something like this.
Public IP ---> Edgerouter eth0
Edgerouter eth1 (100.64.0.0/24) --> tower_1 and clients on that tower
eth2 (100.64.1.0/24) --> tower_2 and clients
[...]
Then CPEs are 100.64.0.x --> NAT to 192.168.x.x or whatever RFC1918 space.
Please note that the above is nothing more than a "scratchpad" example, and not really how you should do it.
Though, really, you should be looking at buying a public block ...
