Its interesting how drupal use cases stumps you even after years. I
was wondering how would one place the same block (lets say user login block) in
different regions on different pages (block visibility) in the same theme of
course. This question just popped without any req for client work, so there is
no urgency but yeah it would be great to know solutions to this use case. I
found
http://drupal.org/project/multiblock
which allows you to create multiple instances, I dont know the internals
so dont know how efficient it is, though usage statistics are pretty good for
this module.