I guess the question is how sophisticated the patched WebBrowser needs to
be. If it is only displaying HTML w/o user interaction, then you're fine off
feeding DB HTML content into the browser. However, if you need advanced
features like pictures, frames, cross-domain links, etc. you might be better
off with an App.
If you're interested, I successfully created a C# Namespace handler, which I
could send you. In that case you would not even have to use your own prefix
(for example if you store HTML pages that are saved from a webserver). Just
intercept any download requests and replace them with HTML content.