I'll take a stab at answering your questions. It's a little complicated, and although
I am not affiliated (at this time) with any of these projects, I'm hoping to save the
developers some time, and also to verify that I have a complete and clear picture of
(I used to develop X11 apps for big companies for years in the past)
First, the X Window System, also known as X11, or just X, uses a server called the
X Server, to display graphics and accept user input from keyboard, mice etc.. Once this
is running, programs (called X clients) can display their GUIs on the X Server. They can be
running on the same system, or any system in the network. (Amazingly flexible)
OK, now the Zaurus as shipped with the Sharp ROM has none of this, and its
graphical system is called Qtopia or Qt for short. But many folks missed the power
of X, and decided to implement an X Server for the Zaurus platform. This can be
done, as was done in many ways as follows:
Pocket Workstation uses a modified VNC (Virtual Network Computing) that uses
the FB (frame buffer) to display the graphics, and chrooted environment that
"fools" LINUX into thinking the / directory is somewhere else, like an SD card.
It also provides a base Debian release in this "fake or auxilliary" / and not any
of the normal Sharp ROM software.
Xqt uses an X Server implemented within the normal Qtopia environment, using
its API for graphics, etc.
Then there is pdaXrom, which is another ROM (sort of my favorite) that provides
a "native" X Server, probably by using the normal XFree86, X.org, or TinyX
X server, the first two which are used by most major LINUX desktop distributions.
OK, now there's pdaXqtrom which is a packaged-up version of pdaXrom, but
uses the Xqt server, and runs on (or really under) the Sharp ROM or variants
like Cacko. This is done again by using a "chrooted" environment. Although
slower than the running the real pdaXrom ROM, it is very flexible and is implemented
by using a couple of loop devices, which are files that are mounted in a way that
they appear and act like partitions. They are typically installed on external media,
but do not have to be. I have been checking this out recently, since it allows the
(extremely stable and predictable) Sharp ROM to be used, and offers great flexibility.
Xqt-Jumbo and Xqt-Super-Jumbo, are from the same person (Meanie) who
put together pdaXqtrom. They are again X environments (apps and a server)
that can be installed as loop devices (compressed RAM filesystems or cramfs
images that can be mounted, and voila you have a system), and I believe they
can also be uncompressed and installed anywhere.
OK, then there is PocketWorkstationXQT which appears to use the Xqt server
instead of the frame-buffer-based modified VNC server for graphics.
SO, I would say you are in the correct forum for any of the above that use Xqt!
Lastly, I think the term "true X desktop" would refer to any of the above environments
in which X clients (programs) will run on, but I think the purists would say that
if the Sharp ROM's Qt panel, etc., are visible and taking up screen space, that its
not a "true" X desktop.
OK, I did my best, and have potentially opened myself up for criticism and correction,
but what the heck!