For the record, I just gave ubuntu-touch-mainline-generic-amd64.img a try on my Intel tablet (Dell Venue 8 Pro).
After downloading I wrote the image to an USB stick with dd, connected the stick using an OTG adaptor and selected it in the boot device dialog .
It booted into gui mode just fine, but lots of stuff (like the orientation sensor or turning off the screen) doesn't work. It's a cool proof of concept anyway, especially since the performance is really good, considering that this is an old Atom tablet and booting from a slow USB drive.
YMMV, because this tablet has some quirks even without UT.
I think this might be worth looking into, because there are a lot of x86 tablets around that are to slow for a heavy Linux desktop with Gnome and all its bells and whistles, but would be ideal as a fast, modern UT device.
Oh, btw, you can make it run in a recent VirtualBox. I had to convert it using something like:
VBoxManage convertfromraw ubuntu-touch-mainline-generic-amd64.img ubports.vdi --format vdi
Make sure to enable multitouch input in the VM settings, if you have a tablet or convertible
: The tablet originally ran regular Win 8 (or 10), and has a "normal" BIOS/EFI.