Whilst the D Box seems an expensive option everything fits like a glove - there is nothing worse than everything not lining up and any loose component wil create booting problems.
A Power Tower is also an option and they appear quite regularly on E Bay. They however the old type AT style cases so are heavy, have an AT power supply which are becoming scare and are more awkward to build in.
Once you've fitted a Mediator you've got the possibilities of dedicated graphics and sound cards and the Spider is excellent for USB devices. Obviously this helps as spares become difficult to source and in my experience a lot of the add ons do not have the life span of the A1200 motherboard.
