Also I am unaware of any Weaver or Picatinny type rings that are lower than classic Weavers. (If you know of any, please correct me)
The only one I know of for sure that is lower than the Weavers is the old Burris Super Lows. I bought three sets of them a very long time ago, did not like them due to their mounting design as I need QD and these are anything but that.
Burris's Part Number is 420091.