Here's a tricky one for you in a similar vain.
I'm using LM6KDE (on the whole really good, but has plenty of bugs/annoyances, KDE4 being one of them, but for now I'll stick to the topic).
Background: I'm updating my home PC which doesn't have an Internet connection available, so I update my work laptop and create an update CD with APTonCD (why does Synaptic insist on only allowing you to add packages from a CD or HTTP/FTP URL? I have a directory full of packages but Synaptic won't allow me to reference it. An ISO image/ folder repo capability would be great. But I digress...). I can't use the restore function with APTonCD but I can tell Synaptic to use the CD as a repo.
So after doing a few package installs I realise that the APT cache is being cleared and not all the packages I want to install on the home PC are available for APTonCD to create on the CD. I changed a Synaptic option to not remove packages from the APT cache, then proceed to download again all the packages I've installed on the laptop already with the "Download Only" option checked in Synaptic. Works great. The packages start showing up in the cache again. Yes, most of the packages are not needed, but this is the only way I can be sure my dependencies, if any, will be fulfilled.
The Issue: What happens next could be a bug, so see if you can replicate it also (if you want to help). Select several packages to reinstall (but we will only download them remember). Synaptic goes through its thing and notifies me that several packages cannot be authenticated, that's fine, the next step should start downloading the packages if all is ok.
However, some packages cannot be found for some reason on my laptop (they're installed, and listed in Synaptic, but Synaptic cannot find them in the repo's). This generates an error that the "package is unavailable and may need to be manually fixed", then you get returned to the Synaptic package list, but nothing shows up in the list! You can click on any section including "all" and nothings there.
The only way to get the list back is to hit the "reload" button to update the package list. You can then cancel the reload as soon as the dialog box appears and the packages all magically reappear. BTW: if you had any packages marked, they will all be unmarked now as well (this is consider a bug also)....
If this is a bug (as it appears) how and where do I file a bug report?
There has to be an easier way to update an offline PC. YUM and YUMEX (for RPM's) let me point to a directory, select what I want and install with dependency checks automatically. Something similar for deb's would be great. Maybe I don't know how to use Synaptic/Aptitude/Adept/Dpkg as well as I think, but that's my experience anyway.
Do not wait, the time will never be "just right".
Start where you stand, and work with what-ever tools
you may have at your command, and better tools will
be found as you go along. -- Napoleon Hill