Cheap- Maxi roughstack. (Switch might not be mechanical, but it's bulletproof.)
Xhaler (And mini-exhaler)
Slightly more but not extravagant: Puresmoker Icon (small) and Prodigy (Medium sized.) (They road tested the prodigy by running over it with a car, then picking it up and vaping it.)
A but more but really well-made: SuperT precise line.
And then, the Golden GreeK stuff: The stealth is small, The GGTS is big. Parts are interchangeable throughout the line. Probably as well made as superT. More flexible. NOT CHEAP.
And there are many more out there...
Ande