OK not a new product, but something I've been using for a while. I finally got around to taking some pictures and showing my method that has worked great at restoring, not just covering, faded trim. It's a pictorial demo so here is the page:
Poorboy's Trim Restorer
The method works very well and lasts.
Here is the before and after:
Before:
After:
After 5 weeks, no dressing and 4 washes - still nice and black: