I think people quit BBSing, not because of the speed (speed was all the same during the transition) but because the internet is just better. The primary reasons for using a BBS were the message areas, the games and the files. By today's standards, their message areas are clumsy and hard to follow, the games are boring and there isn't a file you can't find on the internet. Forums and blogs and threads on Facebook are so much better than the message areas on a BBS. It seems like the only reason to return to BBSing today would be for the nostalgia.
A couple years ago I discovered that there were a ton of people maintaining old BBSes via telnet still, so I downloaded a telnet client that could handle ANSI graphics and spent several hours visiting random systems that ran things like WWIV and Renegade. It was kind of neat, just for the nostalgia, but I haven't been back to any of them since that day. All of them were dead. The message areas all seemed to average about 1 message per month and every message said something like, "Oohhh, this brings back so many memories for me!"
Not to hate on your BBS idea, Q. I will definitely check it out when you set it up as long as it's accessible via the internet. Dialing in via a phone line isn't going to happen for me since none of my computers have modems in them (not even the old ones) and I don't have a phone line in my house. (MagicJack doesn't count.) I don't know how much luck you'll have getting a data connection to work over VoIP. I remember people trying to do things like that on Vonage years ago and it just didn't work. I can't even send faxes with MagicJack.
It could work, though. Cal used to have a telnet PLA BBS running and people used it often, mostly just to play the games he had running.