default home page location

Hi, we have migrated from SP 2007 to 2010.  We have one site that has about 500 subsites each with a default.aspx page set as the default home page.  According to Sharepoint Designer, these files are in a folder called "All Files" and they don't appear to be part of any list, gallery, library, etc..

But I am trying to locate these default home pages programatically(C#).  What's the best way to figure out where these default.aspx pages are located?

Thanks!