Where can I find desktop Ubuntu releases on a vmdk?

Any official or de-facto websites that supply this ?

Details: I specifically need Ubuntu 10.04 LTS desktop version,
in general; ubuntu desktop LTS versions.

You can find many VMs on VMware's site.

Open the site and go to "Virtual Appliances"; Ubuntu LTS 11.4 is one of the many images there.

The newest Ubuntu 11.04 VMware appliance starts out of the box with a desktop looking like Gnome 2.x, but can be transformed to start the Unity desktop from Ubuntu. Contrary to the basic Ubuntu 11.04 image this one has the latest VMware Tools installed.

I have not found any official ubuntu website distributing vmdk's.

According to
http://www.vmware.com/appliances/directory/

very few suppliers of ubuntu desktop on vmdk exist (3 to be exact).

This seems to be focused on vm creation and distribution, and for now I consider this the de-facto website to go to for ubuntu desktop vmdk's:
http://vmplanet.net/

These guys seem to have vm creation and distribution as a side-project to their main line of business:
http://www.quotrader.com/
http://www.bitconstructor.com/