I have not seen such a mods. Still, it's better to have an implementation from the developers, because it will certainly be better and less buggy.
There are two main reasons that games will kick you into third person when driving a vehicle.
1) Vehicle mesh complexity.
If you place a player in the driving seat of a car with a first person perspective you have to make sure the inside of the vehicle looks good with a dashboard, pedals and other driving gubbins. No matter how detailed you make it someone will complain about a minor thing such as the speedometer not giving an accurate reading and such. Mesh complexity was the main reason that a first-person GTA wasn't attempted until very recently.
Is the detailing of the minibike model in 7DtD so bad? I think he looks good enough. You can expect that the detailing of the jeep's interior will be at the same level.
However, of course, disgruntled players will always be. For this, there are modding, players can replace vehicles models with more detailed.
2) Peripheral vision.
It's a lot easier to drive from a third person perspective because a first-person game tends to lack peripheral vision. This isn't really a problem if you're doing a run-and-gun but becomes a major issue when driving.
Yes, I'm the kind of fanny who likes to show the flaws in their own ideas. (British English, it's worse)
Edited : Kind of surprised "fanny" made it through the profanity censor.
This is not a problem, if you can rotate the camera with your mouse, turn your head.
It's a matter of taste. Some like the third-person view, because it gives a larger view zone, and some, like me, like a more realistic and atmospheric view from the first person. I do not play games where used forced third person view. GTA also did not take seriously, but when in GTA 5 appeared the first person mode, I was just ecstatic, it was a shock. In 2005-2008 for the same reason I played at Boiling Point: Road to Hell, and not at GTA San Andreas, because he was a clone of GTA, but with a first-person view. Boiling Point was for me a replacement for GTA. After 2008, they were Far Cry 2 and Arma 2 with civilian mods. All this is due to the fact that GTA had a third-person view, and I hate it. Although the gameplay GTA I really liked.
Therefore, I hate the view from a third party when driving on transport in 7DtD.