I have been researching this and it seems there are 2 programming edits that allow a 32bit version of lion to load and run on core duo machines in developer mode....It is reported that an external Hard Drive pre-loaded with 7.5 and chosen as the startup disk will run in verbose mode or on a virtual PC drive like parallel desktops.There are instructions on several links you can google. I have yet to attempt this on my identical MBP as some users reported earlier OS updates froze some built in applications.
It would be nice to sync my other machines and iphone through icloud but I'm waiting for a more stabile edit. That's all I found to date.
Have fun fixing and finding more value in your electronics.
DS