I'm not sure of specific popular 'business light novel' titles off - hand. However, there could be some in the Japanese market as they are known for a wide variety of light novel genres.
Sometimes, long titles in light novels are used to stand out among a sea of other titles. They might include specific elements or themes to pique the interest of a particular audience.
It might be to give a better sense of the story's scope or unique elements. Long titles can hint at complex plots or multiple aspects of the narrative.
The light novel 'Grimgar of Fantasy and Ash' can be included. The characters are in a harsh and unforgiving world, and there are numerous instances where their survival seems uncertain, similar to the concept of deathflags. Additionally, 'Konosuba: God's Blessing on this Wonderful World!' has comical yet dangerous situations for the characters that can be related to the idea of deathflags in a light - hearted way.
Well, there could be 'Dragonborn: Rise of the Legend'. It might tell the story of a dragonborn's journey to become a great hero, facing various challenges and making allies along the way. Maybe there are epic battles against powerful foes and the discovery of hidden powers. Another could be 'Dragonborn: Quest for the Lost Artifact' where the dragonborn embarks on a dangerous quest to find a very important and powerful artifact that could change the fate of their world.
Some popular ones might include 'Sword Art Online' which has elements that could be considered in the light novel genre. It's about a virtual reality MMORPG where players get trapped inside the game world.
One popular 'shinigami light novel' could be 'Death Note'. It features a shinigami named Ryuk who drops his Death Note into the human world, which then sets off a chain of events with the main character Light using it to try and create a new world order.