We explore mechanical properties of top down fabricated, singly clamped inverted conical GaAs nanowires. Combining nanowire lengths of 2-9 $mu$m with foot diameters of 36-935 nm yields fundamental flexural eigenmodes spanning two orders of magnitude
from 200 kHz to 42 MHz. We extract a size-independent value of Youngs modulus of (45$pm$3) GPa. With foot diameters down to a few tens of nanometers, the investigated nanowires are promising candidates for ultra-flexible and ultra-sensitive nanomechanical devices.
