I'm not aware of any "new" loader available as a bolt-on for an N. But, there are a lot of things in life I'm not aware of, so maybe there is one out there.
That being said, I'd buy another N to put a loader on. I've got 3 8N's; one trailer queen & 2 workers. One of the workers is a 1951 w/ a Freeman loader. If I could only own one N, it would not have a loader on it. The N doesn't have PS, so a loader makes it very difficult to steer. (my wife can't drive it) Stopping it on a down slope w/ a full bucket is a real joy as well. Maneuvering around trees, etc, w/ that bucket out there isn't fun either. Some require you to chain the lift arms down to operate the loader. And, try a simple 5 minute repair job (points replacement) w/ some loaders attached & you will not be happy. Worst of all, the N wasn't designed to carry the weight of the loader & the load, so be prepared for split radius rods & worn out front end parts.
As an alternative, a rear scoop bucket on an N works very well.
As to ease of detachment like the new loaders feature.....it's not going to happen. The old loaders weren't meant to come off & on in 5 minutes like the new ones.
I built a frame to hold the lift cylinders, arms & bucket for my loader. I drive in & 20 - 30 minutes later & a lot of lost fluid, it's off.
There were at least 5 (& probably more) loaders built for N's; Wagner, Freeman, Dearborn, Davis & Sauder come to mind. Each has certain advantages over the other, (e.g., the Sauder does detach quicker) but all share the common disadvantages I mentioned above.