Are there any good technical solutions for extremely long term archiving of data, for example for 25 to 100 years?
Somehow I just don't have a lot of confidence that a SQL 2000 backup file will be usable in court cases or for historians in 25 to 100 years.
This is a customer requirement, not just speculation.
This is comparable to trying to trying to do something useful with a back up for ENIAC or reading Atari Writer wordprocesing files. The hardware doesn't necessarily exist anymore, the storage media is likely corrupt, the professionals for using the technology probably don't exist anymore, etc.
You'll need to convert to text - perhaps XML.
Then upload it to the cloud, make archival copies etc.
I think you need to pick a multi-modal approach.
If you have the budget: http://www.archives.gov/era/papers/thic-04.html