Buying "on hold" domains. Tips for staying out of the sandbox

[alphacooler]

Here is my situation (it is unique). I have a new network of sites all under the same general category. Launching them individually is out due to not wanting to get trapped in the Sandbox.

So I am looking for a domain that is at least 2 years old. Here is the unique part...I don't need the top level page (index page) to rank for anything. Of course some good PR and some relevant IBLs would be nice, but really I just want an OLD domain (that has NOT expired...thus not cleared by Search Engines). The sub directories are the pages that will be optimized.

Question: Will an old domain be sandboxed if it is not currently in the index and then I add content? Do I need to find a domain that is still in the index? Assume in your answer that I can keep the WHOIS info the same.