Horseman sw612d looks interestinghttp://www.kenko-pi.co.jp/horseman/e/SW612D/index.html
I have tried the fotoman dmini, it's good value for what you get.
but you have to calibrate it yourself for your lens. Don't expect it to work straight out of the box. Also be careful to get the right sized cone for your lens.
You can adjust the helicoil for infinity focus by loosening three small screws.
Once calibrated I have enjoyed using it. Even considering mounting some more lens in cones.
I bought it to get some use out of an old style scheider 28mm digitar.