If I remember correctly, Illustrator 10 could save to Illustrator 1.1.
But any other older version (9, 8,7 etc.) should too ... but these will not work for you on your shinny new Intel Mac.
You have three options:
1.) get someone, who has older PowerPC Mac with installed older version of Illustrator
2.) you install an emulator, like Sheepshaver and inside of that MacOS 8 or 9
3.) or you get to someone, who has a PC with installed older versions of Illustrator. Don't forget to firstly convert any fonts inside your .ai file to curves.