Is it possible for CloneDVD (or any other software) to make a full "as-is" copy of a dual-layered DVD with out recompressing anything?

I realize that there are currently no dual-layer DVD burners. What I want to be able to do is create an .ISO or other type of file on the hard disk than can be mounted to a virtual drive (such as Daemon Tools) . That file would not have to be limited to 4.6GB.

Yes, this is possible. You can specify a very large output size (9 GB).

If I set a very large target size, will it "recompress" the video to that (possibly larger) size or just copy it as is?

The latter one.

"Target size sufficient, transcoder disabled", just like e.g. 3.5 GB onto DVD5.

Ah, yes. Don't bother with CloneDVD at all. Go get the freeware DVD Decrypter at http://www.dvddecrypter.com, which will copy the entire DVD, strip macrovision, CSS, region coding AND retain all the ORIGNIAL FILE DATES AND TIMES!

CloneDVD does not remove any type of DVD protection schemes on its own.

Make sure you use DVD Decrypter in ISO mode, and adjust the settings for ISO to select "Remove IFO/BUP PUOs" and deselect "Create MDS File" and change file splitting to NONE if you are writing your ISO to an NTFS formatted hard disk partition.