Download my smbios.plist, edit it for your details as required and you should get System Profiler & about this mac reporting correctly (No more unknown)- See below.
This will report your processor as "Quad-Core Intel Xeon" as Apple do not use Core 2 Quad. Speed is set @ 3.2 GHz but is easy enough to edit. In snow Leo & Leo, Core i7's and core 2 Quads do not show in System Profiler, the plist adds processor info. It will also display your memory correctly with some simple editing for speed - it is set @ 1333. By inputting the processor in System Profiler, you also now have the opportunity to change this info to whatever you want eg:
"Quad-Core Intel Xeon"="Quad-Core Intel i7"
Here is my latest Hack info and below is the plist for download that will show how that is arrived at: