The 4 " x 4" dual display thermometer with outdoor probe gets fairly close functionally.
The unit is on 24/7 and the only buttons are min/max and reset. The C/F is changed with a dip switch on the back.
Calibration isn't dead on and unit to unit variation can be considerable for those mass produced consumer units, but the basics are there. Large dual display. It just needs a tighter calibration tolerance and optimized response characteristics.
The one function that would be nice on the front button would be "averaging period". This is different from sampling rate. The display basically refreshes continuously, but instead of reading what the probe reports back, it would report temperatures that is averaged over a span of (xx seconds, as set by the buttons).
Just because a product is tailored for HVAC doesn't mean the core is better. The CPS 220 scale is a good example. It sucks worse than my postage scale.