I need an overview of what kind of videoprojectors different vendors
offer. They must be suitable for showing powerpointpresenations.
Preferable they should have a memorycardreader and some kind of OS
that could read and present a ppt-file without the need of a portable
laptop connected to the projector.

Tcarls --

A company called Intellimedia, founded by several guys who later when
to work for Gateway Computer, built such a machine in the early 1990s.
 I still have one of their presentation panels here.  However, the
ubiquity of portable computers and the fact that the machine added the
whole cost of computer + operating system + Powerpoint in ROM meant
that it was never very popular.

Best regards,

Omnivorous-GA