  We calculate energies and tensions of closed k-strings in (2+1)-dimensional
SU(N) gauge theories with N=4,5,6,8. When we study the dependence of the ground
state energy on the string length, we find that it is well described by a
Nambu-Goto (NG) free bosonic string for large lengths. At shorter lengths we
see deviations which we fit, and this allows us to control the systematic error
involved in extracting the tension. We compare the resulting string tensions
with Casimir scaling, which we find to be lower than our data by 1%-4%.
Extrapolating our results to N=oo we see that our data fits more naturally to
1/N rather than 1/N^2 corrections. Finally, we see that the full spectrum of
the k-string states falls into sectors that belong to particular irreducible
representations of SU(N).
