If nobody here on the forum can help you, give Glazer's a call.
They may be able to help you with slides for your RB.
I have purchased a couple slides for my RZ from them in the past.

Glazer's Camera
430 8th Avenue North
Seattle, WA 98109
USA
(206) 624-1100

http://www.glazerscamera.com/store/c...RZ+Dark+slides