Even dos had multitasking (TSR), As for multitasking in Dex4u, it not that multitasking is so hard to do, most of our members could have Dex4u multitasking, in less than a week.
Here at Dex4u, we know what is needed to make a successfully OS and that is to do some thing that people want, that you can not do in any other OS, i can use linux or xp for most things, they are fine for desktops, But there is a need for a small, fast singal tasking OS, but unlike dos you can use more than 1MB of memory, have lots of built in functions and be able to use modern hardware usb, dvd,etc.
Look at this example M$ have all the money in the world, but when they made the xbox OS, they made a modern dos, or Dex4u
http://www.extremetech.com/article2/0,1558,1156389,00.asp
You would not say the xbox is backward or old design would, so to answer your ?, i have ask Dex4u members do you want Dex4u to be multitasking and like me they say no, not for the time being.
Here is multitasking in less than 512bytes:
http://board.flatassembler.net/topic.php?t=2164&start=100
you need to get "nanoos2.zip".
So in aswer to your ?, it will not be added to the kernel, but there maybe a multitasking ver of say "gui.dex" made.