When I switched to ADSL I'm pretty sure I was offered the choice of a single public IP address on the outside of my router, or a /29 public range for my home network (and presumably also a public address for
the
external interface of my router). I chose the former and don't regret having done so. I can do a mixture of static and dynamic NAT to allow things from the outside into particular internal hosts if I want do.
This was in 2005, and I can very well believe this choice was not available some time later.
I had a similar setup at one time, I believe it was from Speakeasy but I can't remember, might have been a Covad beta with another provider that my late wife was working for when ADSL was brand new. Not saying it can't be or isn't done; just that for the vast majority (probably something like 90% or more) it isn't. George