sslh[1] usually allows you to reach it even through fairly restrictive firewalls. At least unless they have their certs installed and inspect ssl traffic.
They don't need to have certs installed, since sslh doesn't actually tunnel SSH-over-SSL, it just redirects the connection to the right daemon. Simply pointing ssh to that port would have given up the trick.
Most useful comment in this whole conversation. Incredibly handy for home servers - for which I'd just resigned myself to the fate of running ssh on port 80.
