I picked this up from my MB E320 forum, but I have never used the services.

That said, there are some services that advertise on Ebay that claim they can repair the cluster, for example

BMW INSTRUMENT SPEEDOMETER CLUSTER DASH REPAIR E38 740i 750iL E39 525 530 540 M5 | eBay

If link is broken try searching Ebay for

BMW INSTRUMENT SPEEDOMETER CLUSTER DASH REPAIR