RDA with proper adjustable chamber

[nightshard]

Why are they not made (or do they)?
What i mean is an RDA with the ability to change the chamber size and i don't mean the flimsy derlin drip tip in the plume veil.

Was thinking on a top cap with threads on the inside and several steel cylinders of various heights to be screwed there.

 

[Giraut]

I'm curious: why would you want an adjustable chamber size? Generally speaking, the smaller, the better. I would never want to increase the size of the chamber myself, unless I had a particularly goofy coil to fit inside.

 

[Nayreel]

Or just buy and rda that uses multiple caps such as the tugboat. I can see where you are going with your idea though but wouldn't be any different then carrying around to different top caps if you were wanting to change on the go but why do that?