Perhaps you could build a gas fired kiln with two side-by-side
chambers, then use two burners, also side by side hooked up to
seperate control valves. I wouldn’t think you’d want to use two
pyrometers/thermocouples though, because of the expense. Perhaps the
thermocouple (if you used one) could be made to slide out of one and
into the other. Take a look at www.abana.org, the blacksmithing site
for some info on building gas forges, perhaps this would help.
Mayber there are some ceramicists out there who might know of sites
with kiln plans. Good luck.