There's the Tesla 3, which is exactly like the Stealth with a higher wattage and without the sidecar. I love mine. It's got the internal battery (5000mAh) and can be used as a USB power source.
It had its own tank that goes with it, but it looks like the kit is sold out everywhere. I do see the mod only on DirectVapor though.
Even though it doesn't have the sidecar, it's not huge but it is a little heavy. Smaller than most dual 18650 boxes though.
ed: Size comparison: Pico (single 18650), Tesla 3, Tesla Invader 3 (dual 18650), SMOK AL85 (single 18650)