I've been working hard to uncover further details and, while the company didn't have any further info to share, I have discovered the Quesalupa's key feature: rather than melted cheese sandwiched between a Chalupa shell and grilled flour tortilla like I had earlier speculated, each Quesalupa comes with a Chalupa shell that is stuffed with melted Pepper Jack cheese! The cheese looks to be baked into the shell's interior and fried onsite.
Beyond the special shell, the Quesalupa comes filled with seasoned beef, shredded cheese, and lettuce. There's also a Supreme version that adds diced tomatoes and sour cream.
While the Quesalupa is still in test (I believe it's going into market testing soon), I wouldn't be surprised if it hits nationally later this year.
I would guess a price tag between $2.50 to $3.00. Update: It's currently being tested out in Toledo, Ohio for $2.99.