There is no Mac available with a built-in (or internal) HD DVD player. An after market internal HD DVD drive could probably be added to the Mac Pro, however, have not read of anyone that has done this as of yet.
There probably will not be an HD DVD player offered in any Mac for the foreseeable future as Apple is in the Blu-Ray camp.
If you are talking about connecting one of your Toshiba HD DVD players to a computer, there is no readily available method at this time whether on OS X, Windows, or Linux of getting an HD signal into a computer. The reason for this.... the manufacturers of video cards are afraid of the RIAA and there currently exist no video cards from ATI nor NVidia that provide the connections for component nor HDMI.
Without an internal HD drive, the only HD content available to any OS will be thru a TV tuner card and over-the-air content and that purchased from 360 live.