  We present electron transport measurements on lithographically defined and
etched graphene nanoconstrictions with different aspect ratios including
different lengths (L) and widths (W). A roughly length-independent disorder
induced effective energy gap can be observed around the charge neutrality
point. This energy gap scales inversely with the width even in regimes where
the length of the constriction is smaller than its width (L<W). In very short
constrictions, we observe both resonances due to localized states or charged
islands and an elevated overall conductance level (0.1-1e2/h), which is
strongly length-dependent in the gap region. This makes very short graphene
constrictions interesting for highly transparent graphene tunneling barriers.
