Seth Olsen brought to my attention a nice paper
Direct Measurement of the Membrane Dipole Field in Bicelles Using Vibrational Stark Effect Spectroscopy
These results should provide significant constraints on molecular dynamics simulations on such systems.
Also, this seems a more straightforward approach to investigating ion channels than a recent proposal to use quantum decoherence of NV diamond centres to detect the very small magnetic fields associated with the electrical currents in ion channels. But, I am probably missing something.