Here was me feeling that I wasn't learning stuff with a great deal of utility (to me, that is) and along comes a little golden nugget...

I am familiar with the role of reverse proxies (especially their role in scaling RESTful applications). I have referred to Squid in the past and at my last employer we used BIG-IP to reverse proxy. What I had not realised was that ISA Server can be configured as a reverse proxy too - cool!