(NBC) The makers of campaign bumper stickers are in suspense this morning.

What names will be alongside Obama and McCain in '08? We'll know one of them by tomorrow and in the meantime there's a new flap between the campaigns.

Party officials say John McCain has not settled on a running mate. Barack Obama says he has, but until that promised text message goes out he's hammering on housing. That is, McCain's housing.

He's asked at every stop about his running mate.

Sen. Obama said "I did say that I've made the selection and that's all you're gonna get."

But in Virginia, Barack Obama's stump speech took a turn.

Sen. Obama said "a reporter asked him, 'how many houses do you have?'"

As he seized on comments by John McCain.

When asked how many houses he had during an interview, Sen. McCain replied "I think, ah, I'll have my staff get to you mostly condominiums I'll have to get back to you."

Obama called it a sign McCain is out of touch on the economy.

Sen. Obama said "if your President doesn't hear what's going in your life and doesn't see what's happening in your life, then that President isn't going to be fighting for you."

Within hours, his campaign produced a new ad.

The narrator said "well, it's seven. Seven houses. And here's one house America can't afford to let John McCain move into."

In a statement, McCain's campaign asked, "does a guy who made more than $4 million last year and bought his $1 million mansion with the help of a convicted felon, really want to get into a debate about houses?"

It's a new back-and-forth on the eve of back-to-back conventions.

Will Democrats unite?

Sen. Clinton said "we know we need every Democrat to rally behind Senator Obama's candidacy."

In Florida, Hillary Clinton was asked if her support was tepid.

Sen. Clinton said "well, I am doing everything I can to campaign for Senator Obama."

The latest poll shows 21 percent of Hillary Clinton's supporters back McCain.