So it can be done (http://community.livejournal.com/testlayoutdummy/). And the size of the sidebox is fixed. So I don't think it could just get mangled by different settings.

Questions is:
How practical is it? (i.e. how often will there be new tags?)
And do the mods want it? (They would have do it, or I could keep doing the changes myself. But I'm not sure they want me lurking around on that level :)