Ok, hear me out. This ISN'T a pendulum rocket. Sort of. The engines are still at the top, with fuel and potentially payload below them; but it's not for stability reasons.
One uses Asparagus staging to drop dead weight during the launch, but you also drop useful weight in the form of engines. This design keeps the engines, but still drops the empty fuel tanks. Drop staging.
As you see, the engines are at the top, and fuel tanks hand below them, otherwise bare save for a some struts and fuel lines. Fuel drains up from the bottom tank, and when it's empty, you decouple it. For the particular iteration, it has 12 drop tanks. Earlier tests used more, smaller tanks, but the game won't load the craft if it has more than about 20 tanks. I imagine it has difficulty with the fuel flow calculations.
It has about 4.6KM delta V with a 1.2 TWR via eight vector engines. A more traditional rocket with the same amount of fuel, engines and TWR only has 2.3km delta V.
For this design, I dropped the tank whenever my fuel gauge fell by about 6 tons of CH4.
Everything else proceeds more or less as normal.
Ok, we can skip a bit. Here is when I reached my target AP. Used Win+Shift+S to take the screenshots, which increased my throttle. Messed me up some, as you will see.
Below is proof of orbit. Flubbed it a bit. Was a tad unstable. Needs further design iterations, but hey, these are ugly rockets.
After I tidied up the orbit a little. Heh.
Could have made it uglier, but wanted to spend time with wife and son, so needed to be quick. Pain in the neck, but so is asparagus staging.