I have a CE 6 device with instant-on: the DT Research WebDT430:
https://www.hpcfactor.com/hardware/devices/specification.asp?d=246
You have to set WiFi to be off during suspend, but once you do, it uses so little power during suspend that it can last for well over a week in suspend before running out of power.
See this page for details:
https://www.hpcfactor.com/forums/forums/thread-view.asp?tid=17072&start=46
The tiny Lanhui media player had instant-on too, but mine stopped booting a long time ago, and replacements are impossible to find on eBay these days.