The food lineup for Sunday’s Oak Street Po-Boy Festival has answers for just about any po-boy craving imaginable. At the same time, however, it may pose its own question: Just how far can you take a po-boy and still call it a po-boy?

At 50-plus stands arrayed along the Oak Street commercial corridor and adjacent blocks, restaurants, caterers and food trucks will test the outer limits of po-boy plausibility, with different ideas for how to stuff a po-boy, how to dress it and even the bread on which it’s built.

This year, you’ll find a po-boy by way of a Reuben, though made with corned pork belly and duck liver mousse for good measure (from Boucherie); a shrimp po-boy dressed out like a sushi roll with avocado, cucumber, a spicy, creamy “dragon sauce” and eel sauce (from Seither’s Seafood); and a short-rib po-boy stacked with fried onion rings (from Mahony’s Po-Boy Shop).

The festival began in 2007 as the Po-Boy Preservation Festival, with the subtext of saving the city’s most famous sandwich from the well-marketed competition of chain sub shops. Organizers soon dropped the “preservation” part of the title, however, and in the years since, the pursuit of festival awards (chosen by judges and festivalgoers) and friendly competition between local restaurant pros has produced an annual crop of evermore creative sandwiches.

Some have become perennial attractions — like the fried lobster po-boy from GW Fins, or “the Godfather,” an all-star Italian banquet of sausage, meatballs and brisket under mozzarella and red sauce introduced in 2011 by Vincent’s Italian Cuisine. The smothered rabbit po-boy, which debuted last year from the bayou-side restaurant Voleo’s in Lafitte, is also back. There will be plenty of classic po-boy options, and some that are familiar from other venues. For instance, Pascal’s Manale Restaurant will serve a BBQ shrimp po-boy, a standby from its lunch menu.

But each year, vendors also embrace the opportunity to work outside their accustomed routine. That explains why Parkway Bakery & Tavern, perhaps best known for its roast beef, is instead bringing steamship rounds, the whole steer legs usually seen at banquet-style events. The Parkway crew will slice them to order to accommodate requests for rare to well-done beef.

“That’s my favorite sandwich — a good mid-rare slice, cut to order, with the jus — but if I served that at the restaurant it might confuse my customers, especially the out-of-towners, as to what a real New Orleans roast beef po-boy is,” Parkway manager Justin Kennedy said. “But when you’re at a festival like this, that’s when you can have some fun and do whatever you really want to do.”

Offbeat po-boys are business as usual at the Sammich, the new Maple Street restaurant where Michael Brewer regularly serves po-boys with Korean chicken, duck confit or osso bucco, but he’s still found a way to change his game for Sunday’s festival. He’s teaming up with three other chefs — Tory McPhail, of Commander’s Palace; Chris Montero, of Café B; and Jared Ralls, of La Boca — who also collaborate on a barbecue team for Hogs for the Cause, the pork cook-off and pediatric cancer fundraiser held each March (their Po-Boy Festival booth will raise money for the Hogs for the Cause beneficiaries this year).

The four chefs fixed on the idea of making the Creole classic trout meuniere into a po-boy, and ended up changing nearly every component of the sandwich along the way. Instead of lettuce, it’s dressed with arugula and celery leaf. It has sliced tomatoes, though these are smoked. And standing in for the “pickle element,” as Brewer described it, is a powder made from capers, coriander and mustard seed. But Brewer believes their festival offering is still grounded in the po-boy tradition because it starts with a standard po-boy.

“It’s the bread that ties it all back together; that’s the heart and soul of it,” he said.

Others, however, are even reconfiguring the bread. Kevin White, chef at the Freret Street café Wayfare, will serve a deli-style pastrami sandwich on a po-boy loaf rendered as Jewish rye bread. It’s a custom order from Leidenheimer Baking Co., White explained, that combines characteristics of New Orleans-style French bread and Jewish rye, right down to caraway seeds dotting its surface.

Breads on Oak, one of 16 Oak Street businesses serving po-boys alongside the visiting vendors on Sunday, has devised its own bread — one that looks like a po-boy loaf but has the flaky layers of a croissant.

“We call it the cro-boy,” said proprietor and head baker Sean O’Mahony.

While one version will be filled with seafood au gratin, another will be vegan with a filling of wild mushrooms and the “cro-boy” loaf itself prepared without dairy. That was a particular challenge, O’Mahony allowed, but it fit with his view of the festival.

“It’s just a chance to have fun. Everybody’s having a good time,” he said. “In that setting, you want to do something different from your norm.”

Follow Ian McNulty on Twitter, @IanMcNultyNOLA.