I noted a post at Raymond's blog that it says that there are 2 versions of Fastpush one lite and the other one full. the Lite one can be downloaded here but the Full one is nowhere to find. So the questions is, does it exist? If not, where I can find instructions of how to use FastPush with UltraVNC?

As you say the lite version is available, however I had to remove the much larger full version because of bandwidth issues. You can use Fastpush with UltraVNC by making a subfolder in the Fastpush folder called Ultra. Dump all of the EXEs and DLLs that Ultra uses in there and then push it out using the /ultra switch.