I need a prepreg film much like the kind used on the EC prepreg surface layer, except without the carbon.  

Cytec do a resin film and so do SHD Composites. But I am not sure it would help much. If it is on the surface you may still have surface issues as it does not always work how you expect. I tried some a couple of years ago hoping the extra resin would stop pinholes. Sadly it did not and the results were possibly a little worse at best there was no difference.