FWIW, I think you can make what you need, but you are going to have to piece it together.

If you add a 1x123 exender + an AA cell extender to an "e" series SF body, that should get you the correct length: VG extenders (I think)

Then add a head (KL1 or whatever) and a McE2S "McGizmo" 2 stage tailcap switch. It appears this is also known as an Aleph 2 stage tailap switch. You can see pictures here .

Looks like they are sold at Lighthound and the Sandwich Shoppe.

Not sure if anyone has ever tried it tho.

-john

Edit, oh, and it's going to look kinda crazy too. Basically like this but with the McGizmo tailcap of your choice.