X11 calls can be just forwarded to the currently running server in your machine. The rest, yes, it must be implemented.
PD: I'm not saying IE for Unix would run under that; Solaris it's pretty much post BSD 2.1 and maybe from another Unix branch.
But code from NetBSD could be adapted for such task.
* illumos
* binfmt (Assuming a Linux host)
* qemu
I'm not saying it's zero work, but this looks entirely solvable.