Look into Conetrol rings/mounts. I haven't found anything as low as them - and they're very slick/well made.
You can order a pair of rings and a pair of mounts from Conetrol, and if you'd like to switch either component to the next size up/down, you can post them back and they'll exchange them with the return shipping free of charge.
Not the cheapest rings ($300.00+ depending on features) but they can be adjusted for windage which is a bonus.
To give you an idea of how low they go (Low rings/1" tube):
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