@nprofile1q... me and a friend a while back did some rough calculations. With reasonable state of the art liquid propellants (RP-1 and LOX or so) and engine Isp values and a two stage design, if you just wanted to put a cubesat in LEO and didn't care about being commercially viable wrt payload capacity, IIRC you could build a launch vehicle roughly the volume of a 40ft shipping container (but slightly taller and skinnier)