At the risk of getting myself sucked into another large product, I had the exact same situation and desires. The path I chose to resolve this was:
Switch from the ST Ecobee device driver to yracine’s
Modified that driver in a few dimensions to match my own desires (e.g., no weather data, switch from C to F, etc.)
Added command functions for the Ecobee’s standard 4 “climates”: Awake, Home, Away, Sleep.
Wrote a SmartApp that monitored location.mode, and then sends the appropriate “climate hold” command to the Ecobees when the .mode changes.
I also made all the holds “Until Next Transition”. This puts the thermostat configuration back in the control of the thermostat. I can set different temperatures for the two tstats, and I can also set different schedules (have the bedroom warm up before the downstairs in the winter, for example). And if I wake up earlier than the tstat schedule, the temp gets raised early with me.
My version of the ecobee driver is way out of sync with yracine’s, but you can find it here:
And the SmartApp is here:
Right now, I can’t promise any level of support, but perhaps if there’s enough interest, we can work with Yves to get this forked merged back in… The install instructions are the same as Yves’ (which you can find here: https://github.com/yracine/device-type.myecobee).