xhttp://www.vexlabs.com/images/vex-robots/edu-robot-iso-2.jpg
Ha, if they do come out they could call them Chunk classics-The one, the only, the original. 
Or you could just hack up an rc car you’v got laying around.
Yes, they should be available from Tower Hobbies. Those are RC car wheels made by HPI and I beleive the tires are made by Duratrax. I doubt you’ll see them for sale made specifically for Vex.
Took the words straight out of my mouth:
Yes, those look like RC stadium truck tires, or possibly electric buggy.
Make sure you glue them, though, or they will slip and offer you no traction whatsoever
To glue tires: simply put a smooth bead of CA glue around the rim between the tire and the wheel, in case you aren’t to familiar with RC terminology and technique