I think increased resell value will all depend on whether it will look attractive when you're done. My folks built a matching detached garage when they turned the attached garage into a den. A brick fireplace now sits where the garage door once stood. [The old garage was a side entrance... with the door NOT facing the street.] It all came nicely together with matching brick and matching roof pitch. The den is about 22 x 22 and the new garage is 30 wide and 34 deep.

That's pretty much what they are. A covering with pillars. You can dress it up or down depending on the type of pillars you use and the amount of gingerbread you use. My only advice would be not to make it flat. Make sure it has a decent pitch to it especially if you are in snow country. I'd also make sure it was tall enough for a van to park under with some ease The easiest way to make it blend is to repeat some of the elements of the gingerbread on your house and add it to the carport. The one probably most likely to have been used is what is on the porch area of the house tho I wouldn't limit myself to that if I had something else in mind that was really Victorian.

And why did you change the location of the driveway, and make things difficult for your design? If you liked your design, with the driveway on the left, have you considered simply reversing the plan, since you've relocated the driveway to the right? Good luck with your project.

@Seabornman can I ask why it couldn't be converted? I see them converted into garages all the time in this area (NC). I understand foundation and support might be more of an issue with an addition above it, but I have not seen many completely demolished.