So we keep being asked for simple TIAs as incidental parts of our consulting work. They're useful to have around anyway.
It's a pain getting them to work right if we put SMPSes inside, so we're kicking around the idea of using a rail splitter on our usual 24V wall warts to make +15/-9 or something like that. We'd probably use a TCA0372 and a couple of big caps for the job.
Two-wire warts are isolated, of course, so as long as no bright spark decides to try running our box on the same wart as somebody else's, we should be fine, I think, but we haven't done it before.