Buying OEM when not a system builder is against the T & C.
Currently the exchange rate favours the UK in that we get $1.9 to the £1, yet Vista is not anywhere near the same price.
Mind you it's better than Adobe who seem to believe that $1 = £1
Excellent mod!!!
BTW you can get a lite version of Sketchup from http://sketchup.google.com which Google are giving away so that people can model buildings for Google Earth, so it should be able to do case modelling?