[ghmerrill]

Another option to consider is https://play.google.com/store/apps/detai...reenstream

You can show the contents of your tablet or phone screen in a web browser on another device.

Well, I don't want it merely to display on another device (e.g., a monitor). I want to be able to control MobileSheets from that display device, just as from an attached tablet screen on a tablet.  Think of the phone as a mini-tablet with a mini-screen, but interacting with the larger screen.  Basically, I want the "other device" in this case to become the phone's screen -- touch and all -- so I can fully control MobileSheets from that screen.  This would replace a tablet running MS with a phone/screen combination.

It appears to be potentially doable with a "portable touchscreen monitor" (with it's own battery, and so no need to be plugged into a power supply) and an HDMI connection through an adapter to the phone USB port -- IF the phone can pitch the right image at the touchscreen monitor.  I'm a bit skeptical of that since I suspect the phone may be to stupid to do that.  But if I get a USB-C/HDMI adapter I should be able to test it pretty straightforwardly.

ScreenStream appears to be a remote (one-way, no interaction) presentation app.