Looking for a high optics mount

[Caribouriver]

I tried out a new M&P15-22 today. Remarkable. I hardly had to touch the MBUS sights to get a pretty good pattern at 50 yds. If the darn front post didn't seem to have hair growing out the top, I may have done even better. When I mount an optic, I would like to leave the MBUS rear sight in place. It is about 5/8" thick. "High Profile" sight bases seem to put the 1" scope tube about 9/16" above the rail. I'd like a little more, say 1" between the rail and the scope tube to allow for flaring at the eyepiece and possible dust covers. Does such a mount exist or is it best to just remove the rear sight? Thanks for your suggestions.