Solved.
The problem was not in any way related with the VMware guest 3D support.
3D support was perfectly configured and worked pretty well.
I solved it myself analyzing first if the 3D support was properly setup using mesa-demos package utilities loaded under a Cinnamon session (that was working).
[piggoz@arch2008 bin]$ glxinfo | grep rendering
direct rendering: Yes
[piggoz@arch2008 bin]$ glxheads
glxheads: exercise multiple GLX connections (any key = exit)
Usage:
glxheads xdisplayname ...
Example:
glxheads mars:0 venus:1
Name:
Display: 0x98f4008
Window: 0x2000002
Context: 0x9901628
GL_VERSION: 2.1 Mesa 9.1.4
GL_VENDOR: VMware, Inc.
GL_RENDERER: Gallium 0.4 on SVGA3D; build: RELEASE;
Knowing 3D support was fine and considering this Archlinux virtualbox is rolling upgraded from 2008 to now, I double checked .config folder in my home folder (yes, I like to call directory folders) and found the culprit: the file user inside the subfolder dconf. I simply renamed it dconf.old, loaded gnome-session again and everything was fixed.
PS: there is no need, this days, even with virtual guests under later versions of VMware virtualization software, to make proper modifications to xorg.conf or better xorg.conf.d files. If the kernel support 3D, if DRI and xf86 drivers are properly installed, everything is automagically loaded with the right settings.
To see if your loaded kernel support 3D issue this command:
[piggoz@arch2008 .config]$ lsmod | grep vm
vmwgfx 100089 3
ttm 47188 1 vmwgfx
vmw_balloon 5070 0
drm 186306 4 ttm,vmwgfx
vmw_vmci 46689 0
vmxnet3 37097 0
vmwgfx/drm/ttm is what makes the 3D working this days in recent versions of VMware virtualization software.
It is also important to have vmw_balloon loaded for optimal host/guests memory sharing and reallocation.
Hope this help, this message is for future reference, if I had find something like this posts when I was troubleshooting my problem, I could had save few hours of research and boring experimenting.