Slide mounted RDS do loose their zero on real guns - very much...that why not many people do that. I think if you wanted a low slide mount, a step up like the one Illusion posted would be best. Though as Illusion said. Docters are expensive and difficult to find. But you could always use a few other similar designs. http://www.opticsplanet.net/red-dot-scopes.html
I still like the looks of the tube style RDSs.
There is a Replica AimPoint Micro btw
Sauk Kirsch (a top class GM IPSC shooter) uses a AP Micro.