I downloaded and installed the drivers on my Mac mini with Lion. No DVD drive. Works great with my V700. As others have mentioned though..if you want to use silverfast you'll need to copy it's installation files over. I just used a thumb drive. Or you can share another DVD drive. Or get a USB SuperDrive for the actual disk.
I'm not using silverfast. I'm just scanning with epson scan direct into cs5. Works great for me...