I'd like to run an entire PortableApps suite from CD...

But why not try it out yourself?
CDs are cheaper than dirt - and you can probably use a CR-RW to test it if you need to tweak it.

None of the settings are going to be saved and the apps are going to keep saying that it can't write it's settings with pop-ups.

I seriously don't recommend it.

Most of the apps have an option "RunLocally" in their INI files. Read Other\Source\readme.txt for more information (in X:\PortableApps\AppNamePortable). To use this, first of all set up your settings as you want them - after putting it on a CD you'll not be able to change them again (other than by manually rewriting part of a CD-RW/CD+RW). Then, copy the AppNamePortable.ini file from Other\Source to the directory in which AppNamePortable.exe is, and change the RunLocally line to RunLocally=true

Many of the newer drop remove this functionality though, and off the top of my head I can't remember what they do instead - whether they ignore it and do it anyway or just don't support it. You'd need to try it.

By the way, it'll be a lot faster in instances like this if you search... unfortunately in this instance, as you see if you follow the link, the three-character minimum length for indexing ruins that... try this.