Let me qualify this post by first saying I ONLY use Hybrid style mechanical mods, I own eight of them currently including a few I've modified myself to be Hybrids.
Having said that I urge you to continue to look at the SMPL, the button is very recessed when installed, easily 2-3mm recessed and it has never once come close to autofiring in my pocket, bag, car, anywhere. Honestly It doesn't have a lock because I don't think the design needs one. The SMPL is by far my favorite mod I own, it gets used for hours every day and has never given me a single issue. I know you said magnets, but the spring switch of the SMPL is pretty awesome IMO.
If you like the Stingray X you can also modify a Nemesis to be very similar, hybrid top caps and magnetic switch upgrades are available and numerous for the Nemesis.
As far as exactly meeting your needs, the Zombi by Ritual Machine would be a great option -
The Zombi by Ritual Machine | VapeRev