Yesterday, I received an answer from Excelon, the manufacturers of Stylus Studio, my beloved XML/XSLT IDE, concerning their current lack of OASIS entity catalog support. They said they (at least) knew that is wasn't there, but that I was the first customer actually requesting it.
Strange. I've been using OASIS catalogs since the SGML-era (yup, I'm in this circus for that long), and especially for DTD-guided authoring and validation, I couldn't live without it. And I can't imagine how people working with XML Schema (the horror) or RELAXNG cope with centralized installation and administration of their documentation grammars without them.
Since we use the Walsh entity resolver for Forrest, I'd rather see all of my tools support those catalogs. Currently only Softquad XMetal does to a decent degree.