I have a like-new (purchased new by me from OPT this summer) Losmandy DSBS side by side plate. It fits onto a G11-style saddle plate and has two G11-style saddle plates, one at each end. From Losmandy's website: "Side by side plate. Incorporates two saddle plates mounted parallel to each other. Used for mounting two optical systems side by side, by rotating the G-11 saddle 90 degrees.
Wt. 7.25 lbs., Total thickness 1.5", Saddle plate separation 10.0", center to center." Sells new for $240; I'll sell this one for $200 shipped CONUS. I accept Paypal (no surcharge) or postal money orders. Astromarters with great feedback can send a personal check.