For applications such as these, the HVCB series from Stackpole provides a high precision, low VCR chip resistor with high stability. The HVCB is available in resistance values from 10K to 50G, in tolerances as low as 0.1% and TCR as low as 25ppm. Stackpole has recently expanded the available stock for the HVCB series.
Inventory now includes more values in 1206 and 2512 chip sizes and added common values in the 0805 chip size, in 0.1% tolerance and 25ppm or 50ppm TCR depending on size. Applications include high voltage power supplies, voltage dividers, and a variety of medical applications such as patient monitoring, medical imaging, instrumentation, defibrillators, as well as applications for test and analysis, and data acquisition / communication / and monitoring. Pricing varies with size, tolerance, TCR and resistance.