Prodigy V3.1 by puresmoker.com - all mechanical and can take a beating. Nice battery life. Battery lasts me all day plus some.
Something a little smaller? Icon by puresmoker.com - all mechanical and can take a beating just like it's big brother the Prodigy. Battery life is shorter than the Prodigy but still lasts half a day (I vape heavily 6-7ml a day).
The Buzz by notcigs.com- a freight train could run one of these over and it would survive. Not all mechanical but still very durable. Variable voltage also.
Megalodon by electronicstix.com - all mechanical and durable. Can be broken down to a tiny size to fit one single cr123a battery for stealth vaping (hides in my girlie hands). It will also accommodate just about any battery you put in it. You can also stack batteries for 6V vaping.
This. EXACTLY.
I have a Buzz and 2 Prodigy V3's. The Buzz is tough. The V3 is impossible to break. Unless you crack the threads or tube, there is nothing to break.
If you are around coolant, VV may be a problem. The circuit will short if it gets wet.
The saber touch switch would concern me a bit. Coolant and metal shavings (especially ductile iron) may cause problems. Also, I do not believe it can be activated while wearing gloves.