Aguas,
This is the one I can find.
http://atsearch.autotrader.co.uk/topgear/cars_advert?id=201304186337681
I am a big lover of white car with black roof too. It will look great on the CX-5.
I had recently applied some 3M Scotchprint 1080 vinyl wrap on the CX-5,
http://www.mazdas247.com/forum/showthread.php?123828858-My-mods-on-the-CX-5-vinyl-wrapping/page2
3M have gloss black or even other color pattern to choose.
With a second hand, I am sure you can do it yourself and it's a dry application(no soap water of wet area). For the size of the roof, you are expecting about material around $100 + labor(which is another $200-300 in my area). However, without enough experience, vinyl wrapping is not going to look 100% perfect perfect. But, it's reversible. I plan to do the roof one day on my our red CX-5, I just don't have time right now. Keep in mind that vinyl wrapping is not permanent and one day, the vinyl will lift and loose adhesion. I have seen someone had problem wrapping their 350z. Although you can use primer 94 adhesion promotor to make the wrap stick to the surface, that's not reversible and you better paint it at that point.
On the other hand, to paint the roof professionally, you are looking about $500-1000.
And I do not think that you want to do plastidip because it will not give your the gloss black, it's more for matte, even with glossifier and metallic addition, it's better for dark gun metal.
Hope this help and Good luck!
I'm a sucker for a white vehicle with a black roof (often associated with a panoramic sunroof), and I'm eager to have my wife's new CX-5 roof wrapped with a gloss black vinyl. Although I don't expect the cost to be too much, I'd like to see if any of the 247 crowd has had their roof vinyl wrapped, sprayed or even PD'd before I sell this idea to Mrs. Aguas. I did see a post recently by a member that had his black roof wrapped with a carbon fiber printed vinyle to protect it from sand from his roof mounted kayaks, but seeing a grayish roof on a black vehicle isn't quite the same.