Is it possible to run Ubuntu in JSLinux ?
Here is today's Slashdot post about JSLinux.
No. JSLinux only implements a cpu, interrupt controller, interrupt timer and a serial port. That is quite far from the Ubuntu Hardware Requirements, such as a hard drive, graphics card etc.
If you had lots of time, you could probably create a suitable image based on Ubuntu, but it would be too far from the regular Ubuntu experience to be called an Ubuntu remix. See the trademark policy.