Speculation continues to suggest that , and perhaps kick off that broader second M&A wave.

But in each individual sector, like engineering and architecture, the analysis takes a more-directed tack.

For Mick Morrissey, expectations of more M&A are propelled in part by today's "commodity-rich environment," which is seeing increasing cross-border activity as engineering firms expand to take advantage of mining sector opportunities, such as the August acquisition by San Diego-based Tetra Tech, a $1.1 billion market cap company, of Metalica Consultores, a Chilean mining and engineering firm, and the purchase of 60% of Portland, Ore.-based Otek by South Korea's HamniParsons.

That could get the second wave started, in Morrissey's view, as more foreign companies see U.S. infrastructure-based opportunities. He expects cash-strapped state governments to boost this spending on the cheap, through "public/private" initiatives that allow for the investment of private capital into projects like highways and bridges. "Politically, that makes a lot of sense. The states can't do it themselves and there's trillions of dollars waiting on the sidelines." he argues.

"Canadian firms and firms from Asia and Australia" are all familiar with the "public/private" model, and are "looking to purchase platform firms in the U.S.," he says. "They're willing to pay seven to eight times earnings or one to 1.2 times revenues."