  We report precise simulations of phi^4 theory in the Ising limit. A recent
technique to stochastically evaluate the all-order strong coupling expansion is
combined with exact identities in the closely related Aizenman random current
representation. In this way high precision estimates of the renormalized
coupling are possible at low CPU cost. As a sample application we present
results for the unbroken phase of the Ising model in dimensions 3, 4 and 5 and
investigate the question of triviality by studying a finite size scaling
continuum limit.
