DSS live in Windows is an example of this, and why some some similar threads appear to have a bit of confusion. Whereas Indi's "live" is a session sharing, live stacking does a quick realtime denoise stack of a preview of stored images, reading them from a folder as they come in. It would require some reworking of the graphics preview system to use or wrap a stacker.
Siril, a Linux based stacker I've been using does have a few command line script options and could possibly be pressed into service with some work/collab with their devs. Another option would be to come up with a standalone live stacker for Linux, which might be a fun idea to approach the Siril guys with.
It's not part of Ekos, but it's a python tool to repeatedly scan a folder for new FITS files and live stack them as they come in, so you could possibly examine the INDI folder that kstars points to and view the stack with this one.
Have to say, would be very nice to have a Live Stacking Feature within Ekos too, especially one that handles the multiple filters on Mono cameras as well (and the file layout that Ekos puts its files into).