I am asked this question daily, but because of Jon Toigo's article in searchstorage we have gotten a flurry of calls today. NetApp does provide transferable licenses. You just have to negotiate it into your Purchase Order when you buy new equipment.
By the way, Dave Hitz was reviewing the issue two years ago.
From: Dave Hitz (firstname.lastname@example.org)
Date: Tue May 06 2003 - 12:50:50 EDT
EVP Engineering and Co-Founder
By the way, IBM figured it out years ago.