I tried in the following note<http://www.cse.chalmers.se/~coquand/mod2.pdf> to present as simply as possible
the model structure discovered by
Christian Sattler on a large class of presheaf categories (the hypotheses
I have on the base category are not minimal). The goal of the note is only
to describe what are the fibrations, cofibrations and weak equivalence
without giving proofs (only the 2 first sections are necessary; one remark
however is that the proofs are all effective).
 It is not clear at this point if the categories obtained by localising at weak
equivalences are equivalent to the homotopy category of Top.
 Thierry