  We propose determining |V_{ub}| from inclusive semileptonic B decay using
combined cuts on the leptonic and hadronic invariant masses to eliminate the
b->c background. Compared to a pure dilepton invariant mass cut, the
uncertainty from unknown order (\Lambda_{QCD}/m_b)^3 terms in the OPE is
significantly reduced and the fraction of b->u events is roughly doubled.
Compared to a pure hadronic invariant mass cut, the uncertainty from the
unknown light-cone distribution function of the b quark is significantly
reduced. We find that |V_{ub}| can be determined with theoretical uncertainty
at the 5-10% level.
