Finally have it there, and with a little manual compilation, WiFi is there.
It's really, really nice.
At least since early this morning, my downloads here at home are bounded above at 1 Mb/s; that bound should be more like eight or nine megabits per second. Mediacom initially claimed maintenance was underway, and check back again in an hour. Now they say someone has to come out and take a look... and the soonest that can happen is in over a week.
Last night I used BitTorrent to grab the Jaunty Jackalope Beta ISO file, a perfectly legal use of p2p. I asked whether that had anything to do with it, and the person at the other end of the phone was non-committal, though she did say that Medicaom would suspend my Internet service if they found me "downloading movies". She was evasive about whether there was some threshhold on bandwidth usage, and it's not clear to me how they can tell legitimate uses of p2p (e.g. for distributing Open Source software, or using Hulu et al.) from illegitimate uses.
Maybe I will end up suggesting that they use their cable modem in a painful fashion... we'll see.
UPDATE: Things seem to be back to normal; this morning speedtest.net said I was getting data from the Bahamas at 6.6 Mb/s. Not shabby, though that 20 Mb/s is still tempting.