...and sure enough.
I picked up a six-pack of AD7713AN
"CMOS, Low Power 24-Bit Sigma-Delta, Signal Conditioning ADC with Matched RTD Current Sources"
http://www.analog.com/en/prod/0,2877,AD7713,00.html
...and two AD580 and two REF192FS.
http://www.analog.com/en/prod/0,2877,AD580,00.html
http://www.analog.com/en/prod/0,,769_838_REF192,00.html
Now...
I've already got too many things going on (as if no one knew!) so this is probably going to sit on ice for a while, but I thought I'd put the offer forward; if anyone is interested in building a similar circuit, I'll supply the ADCs and the volt references. Heck, I'll even cover the cost of the PCBs.