I, too, work in Visio with data center floor plans and other facility arrangements.

Reference the "ruler & grid" option, I only use them for reference...not to scale a floor plan. Visio comes with standard stencils to build floor plans with in the Professional version (I do not know if your 2007 version the Professional or Standard version).

Edit: I tried to upload a Visio Stencil that contains floor tiles (and other equipment options) that you could have used to build upon but, alas, this forum attachment process did not recognize the file (gave me an "invalid File" response)....sorry bout that. However, if you google "Visio Stencils" you may come up with some options that may be of assistance (i.e., http://www.visiocafe.com/ for one...there are others).

You did not ask (and I don't know you experience level) but, here are some links that may be of assistance to you as you work with Visio:

http://msdn.microsoft.com/en-us/libr...ffice.10).aspx.
http://www.visguy.com/

Hope this helps.