You might be able to launch apps by intent from the web but I'm not sure whether that's still possible. You could then use the undocumented intent to specify a server URL and form_id and launch that in Collect (I could write up some details if you validate that intents work and that seems interesting). The downside is that there has to be one project (e.g. the demo project) in Collect for this to work (see this thread).
We explored launching Collect with a configuration URL a while back but didn't see a good way to get a config in.