Pearls of MOSSy Wisdom

1. Variation Sites are based off Publishing Sites.  This may be obvious, but I've talked with a Microsoft MOSS Tech Support person who did not know this.
2. According to Microsoft, Variations may break with "heavy customization".  My site customizations include: MasterPages, Page Layouts, WebParts (SharePoint Designer and Visual Studio created), and StyleSheets.  Microsoft suggested "rolling back the customizations" to test this.  This is not possible at this time, but they keep telling me that the level of customization is the main suspect in my Variations not working.  (I could rant on this concept for days).
3. A site collection restored from backup (MOSS GUI Backup/Restore) will NOT be a functional Variations site.  As it turns out, the backup process does not back up the Timer Jobs associated with Variations so your restored copy will no longer function correctly in creating new variations.  And I doubt new page/page changes propagation will work either.  To "solve" this, Microsoft suggested before restoring the site that you make a new blank site (to have the jobs created) and then restore on top of the site with your backup.  I have yet to get this working.
4. Do not "experiment" with Variations.  If you need them, use them.  If you don't, DO NOT even think about the Variations pages.  Once you create a variation source label you cannot remove it.  (You can remove the other labels easily, though).  Now, technically, you can remove a source label.  SharePoint will let you in the GUI.  But your site is messed up after that as the structure changes SharePoint makes are not reversable.
5. Do all initial variation settings (ie, creating the source label) BEFORE any content.  In fact, it should be one of the first things you do.  Variations creates several sub-folders (Style Library is one folder that gets language sub-folders) and if you have alot of content existing, they may not get created.
6. Once you commit to language variations, you will need to re-think every custom webpart you make.  I have made multi-lingual webparts (from references on other blogs and based on my own findings) and have had to re-work previously built webparts that were not very well thought out in a multi-lingual sense.  SharePoint Designer web parts are not the easiest things to make multi-lingual.  I will post on Studio-based web parts later.

That's all I can think about right now, but I may augment this post later.  But I have the site up and running (though the translations are not published yet).  If you have any questions or comments, feel free to ask.  I've been through alot with variations, hopefully I can help before you hit any pitfalls.