Have a Knights Armament Co. vertical Aimpoint mount (part #98073, description: 30mm Reflex Mount)
for flattop uppers. According to KAC, you can use it for other 30mm devices, but I've only used it on the Aimpoint.
Excellent condition in box.
Also have a Trijcion TA51 ACOG Flattop Mount. Used it on a TA11, but it also works with the 4x ACOGs, (maybe the compacts, but I'm not sure about that). Dual thumbscrews attach the mount to the rail.
Excellent condition with both screws.
*Edited to add: TA51 is sold, KAC mount still available.
I take Paypal or MO.