  We present evidence for an exotic gapless insulating phase of hard-core
bosons on multi-leg ladders with a density commensurate with the number of
legs. In particular, we study in detail a model of bosons moving with direct
hopping and frustrating ring exchange on a 3-leg ladder at $\nu=1/3$ filling.
For sufficiently large ring exchange, the system is insulating along the ladder
but has two gapless modes and power law transverse density correlations at
incommensurate wave vectors. We propose a determinantal wave function for this
phase and find excellent comparison between variational Monte Carlo and density
matrix renormalization group calculations on the model Hamiltonian, thus
providing strong evidence for the existence of this exotic phase. Finally, we
discuss extensions of our results to other $N$-leg systems and to $N$-layer
two-dimensional structures.
