Well, I think I might have got an insight as to where the SIZE of this MASTECH MS5308 came from, and the "odd" choice of battery compartment mouldings.
Probably the most expensive development cost for products of this type was the case tooling, which can run into thousands of dollars. So, if you can share tooling costs across products, so much the better.
Check out the Mastech MS7212.
http://www.multimeterwarehouse.com/CalibratorMS7212f.htm It is a "Process Calibrator" which is basically a multimeter, but has the ability to OUTPUT certain reference voltages, currents and suchlike. Guess what? It's in (very nearly) the same case. Now, this device NEEDS two sets of batteries, so that it can both output a reference current and measure stuff, too, which the inputs and outputs are isolated, I dare say.
Also, this device has many more buttons, in keeping with its many more functions. That's fine, but that gave the designer of the 5308 with its fewer buttons a problem. How to position said buttons? The answer was to make them HUGE. On any PC keyboard, a large "enter" key sounds sensible - on the MS5308 it is a key that you may be hard pushed to ever, um, push.
Dave S. I hadn't really thought about "LCR Meter Envy" I shall try that, the next time me and a few friends are comparing capacitors...