And ne'er a dissenting voice was heard

So far, I'm only aware of two instances were anything related to immigration or similar matters has even been discussed at the GOP convention:

1. Massachusetts Governor Mitt Romney in his speech: "[American workers are threatened by] low-cost, highly-skilled labor from abroad"

2. "[Kansas] Republican challenger Kris Kobach said Monday that Democratic Rep. Dennis Moore "placed American citizens at risk" by voting against a proposal to allow troops to patrol U.S. borders... "How many terrorists will enter the United States before my opponent realizes that we must close the border to terrorists?" [he said during his 47-second speech]

UPDATE: The column "GOP ducks discussion on illegal immigration" has more on Tancredo's press conference:

Tancredo held a press conference to express his displeasure - in a kosher New York restaurant staffed by foreign accents from around the globe. Outside on Broadway, the international hordes went about their business.

Also note that Tancredo's fellow panelists were New Yorkers who swim easily in the sea of diversity. They didn't reflect any white-bread fears of brown-skinned masses taking over.

Some panelists told reporters that they disagreed with the fiery congressman on many issues. But they clearly shared his concern that illegal immigration threatens both Americans' livelihoods and their lives...

"There are a billion willing workers," Tancredo [, speaking about Bush's "guest worker" plan] told the press conference, "all of them willing to work for less than someone (an American) already employed."

...[Matthew Reindl, whose family owns a carpentry shop on Long Island] noted that he provides his workers with good wages, health insurance and workers' compensation coverage. His lawbreaking competitors do none of these things. As a result, his labor costs are at least 60 percent higher than theirs...

That latter certainly sounds like something a Democrat could really sink his teeth into: "illegally lowering wages for American workers, trying to put American jobs on eBay, etc. etc."

Other reports on Tancredo's efforts in NYC start here.