It strikes me that you may be able to do this by duplicating the single source layout. Then you can change the properties of each one to a specific set of conditional build tags and output path. You can even use the Batch Generate feature to create all the outputs at the same time. I have a blog post on this which may prove useful.
You can create multiple single-source layouts (also multiple FlashHelp layouts), each with a different TOC/CBT/UDV specification. You can then easily use a batch command to generate/publish all your different layouts at once. (You can do this from RoboHelp, but you can also use a .bat file/the cmd.)
In RH7, the batch function is in the File menu. I don't know where it's hidden in RH8.
As for publishing to your customers, do you use Online Help, or do you deliver the files? In the first case, you can use the publishing function to publish directly after generating.
If you send zips to your customers, perhaps a developer can write you a script to quickly zip each build and put the files in the directory you use for publishing.
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