Very much related to this, where I suggest a very simple guideline - don't answer unless you can point to something that exists prior to your answer being written.
That said .. if you know something is open source, or can be modified with some kind of plug-in, and a combinations of plugins or known modifications could suit the criteria laid out by the question author, and the question author indicates that they're open to recommendations that entail a little develop-y stuff - fine. But we're getting more into granular case-by-case criteria there.
There's nothing wrong with saying:
I'm confident that what you want doesn't exist exactly how you laid it out, but [xyz] matches most of your criteria, and if used in conjunction with [abc], most of your needs would be met.
That's a far cry from you probably need to consult a developer to have something written to suit your need though.
Just make sure that answers point to something immediately actionable by the question author, and I think we're good.