Unfortunately, there's nothing out there for something like this. If you try to put any sort of "sock" on it, it will get sucked in. To prevent that, it needs some sort of mesh screen. You'd need a really big version of something like this that you can stick on and then cover up easily.
Alternatively, get a normal intake with filter and swap out the entire tube for when you want to run the bell mouth at the track or something. That's what I do.
