They came stock on the 1990 Cannondale SM2000, all Shimano XT. I'd say they were probably high-end or near it.

http://www.vintagecannondale.com/year/1990/1990.pdf

Here's a review of spokes, laced to these rims. No reports of the rims collapsing:

http://www.mtbr.com/reviews/Spoke/product_23110.shtml

Do you know German? A Google search yields quite a few German language web hits.

Sorry, no first hand experience.