Serverroom

We have to design a new serverroom here. Now I know there is a site weher you can build/design this online. Only, lost the URL. Does someone know which site it is?
Second, does someone have a checklist which I can use when drawing/writing a plan. (checklist should include power redundancy, cabling, security etc.. and what i should keep in mind)
All help is welcome.
THX, Luc.