I can see a possible scenario where Trump takes on Cruz as his veep. Something like Kennedy and Johnson, Cruz would be used to get not just delegates but the votes of those like many of the name-calling yahoos here always whining about being mistreated.
Cruz would pretty much be regarded by Trump’s people as a potted plant, in that the office has been called “about as worthless as a bucket of warm spit.”
But he would probably be good at it. He could fetch Melania cold drinks and bird-dog her staff.
A Trump/Cruz ticket is the perfect strategy for beating the GOPe but there are personal biases at work. My guess is Trump can put that aside, but Ted has been the target of a lot more humiliation from Trump than vice versa making Ted ripe for the GOPe's soothing lies. "We want you Ted! Help us destroy Trump! There's a place for you on the ticket..."
The best case would be if Ted is as cold and calculating as some of his critics claim. Then he would forget about all the personal stuff and do what's necessary to stop the GOPe at the convention. I don't know enough about the guy to even guess what he might do.