Basically I will be calibrating circuits to a high degree of precision. Keeping it minimalistic, I figure all I needed for that are resistor networks, voltmeters and a few high precision voltage references. Like I said it has to be very high precision, so I figure the voltage differences would be in the microvolt range.
I've looked at different options from expensive high precision lab voltmeters to oscilloscope preamps (I suppose it could be adapted as a preamp for a voltmeter?). They are all so expensive.
Since my circuits have to work both with AC and DC signals, we could simplify everything by only calibrating against DC signals. So noise becomes a lot less of a problem, since it's DC.
So now I figure, just get a Low Noise Instrumentation Amplifier (or preamp) that will amplify by a fixed factor of 1000, to bring the microvolt to millivolt range, which my multimeter can then measure.
Is there any problem with this whole approach? If you have really good schematic designs for an Instrumentation LNA, can you guys share it with me?