  A model of a clean two-band s-wave superconductor with cylindrical Fermi
surfaces, different Fermi velocities v_{1,2}, and a general 2x2 coupling matrix
V_{alpha beta} is used to study the order parameter distribution in vortex
lattices. The Eilenberger weak coupling formalism is used to calculate
numerically the spatial distributions of the pairing amplitudes Delta_1_ and
Delta_2_ of the two bands for vortices parallel to the Fermi cylinders. For
generic values of the interband coupling V_{12}, it is shown that,
independently of the couplings V_{alpha beta}, of the ratio v_1 /v_2, of the
temperature, and the applied field, the length scales of spatial variation of
Delta_1 and of Delta_2 are the same within the accuracy of our calculations.
The only exception from this single length-scale behavior is found for V_{12}
--> 0, i.e., for nearly decoupled bands.
