You can search the BioModels database with EC numbers, and it will find SBML models if they have been annotated with the corresponding terms.

BioModels Database serves as a reliable repository of computational models of biological processes. It hosts models described in peer-reviewed scientific literature and models generated automatically from pathway resources (Path2Models). A large number of models collected from literature are manually curated and semantically enriched with cross-references from external data resources. The resource allows scientific community to store, search and retrieve mathematical models of their interest. In addition, features such as generation of sub-models, online simulation, conversion of models into different representational formats, and programmatic access via web services, are provided.

For instance, searching for 3.4.11.4 (N-terminal cleavage of tripeptides) yields:

• Thiele2013 - Human metabolism global reconstruction (Recon 2)
• Hoppe2012 - Predicting changes in metabolic function using transcript profiles

Also, there was a large-scale conversion of KEGG models into SBML. You can find the details in this article.

If you have pathway IDs, then you can use KEGG Rest API to retrieve the kgml file and probably convert it into SBML models using KEGGtranslator or KEGG CONVERTER, although I have to say that I haven't tried converting a kgml file to an SBML model.