When you say a "rendered video walkthrough" do you talk of something like this ? If yes LightUp will be fine for you! It can made even a rendered video walkthrough interactive by the user who has not Sketchup or LightUp !!! Also for the Net or IPad... http://www.youtube.com/watch?v=JH_WTmsDgVw&list=UUGGG74ibHIHoEsSuyLUkOfg http://www.youtube.com/watch?v=8PDeAlFFERM

thanks so much for all your help and suggestions. hopefully i can produce something using the tools you have all recommended! much appreciated