I've finally gotten around to adding my H2-regulated SF star maker to enzo-dev, which is what I used for Kuhlen et al. (2012), ApJ, 749, 36. This pull request introduces two new features:
1) The H2-regulated SF (star_maker_h2reg.F), which you can select by setting StarParticleCreation = 2048. The H2 abundance is determined using the Krumholz, McKee, & Tumlinson (2009) prescription.
2) The ability to create star particles only once per root grid time step and only on MaximumRefinementLevel grids, but with stellar mass that is proportional to the root grid time step (see Kravtsov 2003). This results in more massive and fewer star particles, which can help with computational efficiency. At the moment this is only implemented for the new H2REG_STAR star maker, but it would be trivial to export to other star makers. Select by setting StarFormationOncePerRootGridTimeStep = 1.
I included extensive documentation of this new star maker.
Thanks for adding this to the public Enzo repo, Mike!