I stumbled upon the works of Tony Chen, a dynamic artist who resides in California. Over on his DA Web Page, he has a host of concept designs that he does as part of his course studies - sometimes he drafts them with markers and pens, before he initiates 3D modeling. Check out these designs of sports cars and compact SUVs that he's done for the Audi Motor Company.
These next two images are actually "sketches" that he did, for BMW and Mercedes Benz Concept Cars:
Although he's still a student, Tony has an advanced design flare that almost reminds me of Pro Concept Artist Scott Robertson [Samples of Scott's outstanding work are posted HERE].
BTW, the article containing the TRON: LEGACY hoverbike designs has been updated with 2 new pics: HERE
And Visit the blog archives to see more cool concept vehicles: HERE