The already crowded field of wealth management firms who want to go national is getting more crowded, still.

Omaha, Neb.-based Carson Wealth Management Group, the top independent broker/dealer advisor in Registered Rep.’s most recent ranking, has opened two new offices in Washington state, bringing its total to three offices. Carson hopes to add five more in other regions within a year.

In the northeast, RIA Merion Wealth Partners, based in Berwyn, Pa., has joined forces with seven regional firms with an eye to eventually having around 80 offices around the country, up from four today.

Carson and Merion are in good company: last month California-based RIA Aspiriant completed a deal to widen its’ footprint by taking over six Deloitte Investment Advisors offices in the midwest and northeast, keeping pace with other fast-growing, high-profile firms such as HighTower Advisors and Edelman Financial Services.

And two of the industry’s most aggressive RIA aggregators or “roll-up” firms, Focus Financial and United Capital, continue to steadily add new firms to their respective rosters. Indeed, RIA consolidators have acquired 20 of 63, or nearly one-third of RIA sellers with over $100 million in assets to date this year, according to David DeVoe, director of strategic business development for Schwab Advisor Services.

To succeed, firms with national ambitions like Merion and Carson will have to both add value to firms they acquire and use scale to their advantage, said Dan Inveen, principal and director of research for FA Insight, an industry consulting firm based in Tacoma, Wa.

“It’s a bold move to launch a firm in this space,” Inveen said, noting that some roll-up firms like Nashville-based WealthTrust have stopped growing. See “The RIA Roll-Up Unraveling.”

“There are a lot of willing sellers out there, which should only escalate in numbers,” he said, “but there’s also a lot of competition, including from local market leaders who want to dominate a region. And RIAs have more information, resources and platforms available to them than ever before. Aggregators have their work cut out for them.”

Despite the congestion, DeVoe and other industry observers believe there is still an opportunity for acquisition-minded firms with national aspirations.

“It’s still a wide-open field,” said industry analyst Alois Pirker, research director for Aite Group of Boston. “The first mover is not necessarily the winner.”

“There still aren’t any really big aggregators out there in the scheme of things,” noted Tim Welsh, president of Nexus Strategy of Larkspur, California. “The marketplace is still very fragmented, and there definitely is room for more players. You could even say the bar to succeed is fairly low, if $1 billion in assets is your benchmark.”

In fact, Merion, which currently has $250 million in assets under management, hopes to reach the $1 billion mark by the first quarter of 2011, said Bob Andres, chief investment officer and strategist for Merion, with an eventual goal of around $8 billion in assets under management.

Merion is set up as a partnership group and is offering a full-service platform to independent registered investment advisors. Advisors can join in three ways, said Paul Beideman, Merion’s chairman and chief executive officer: as affiliates, in exchange for a percentage of gross revenues; through a merger with Merion or as a “regional launch partner,” merging with Merion and receiving a share of revenues from other local firms it brings into the fold.

Asked if Merion’s business model included an exit strategy where partners would cash out in a sale or public stock offering, Beideman said the firm was “built to last. We see a real opportunity in the marketplace trying to help independent advisors do an outstanding job meeting the needs of their clients and to be an owner of a successful, growing organization.”

Why should advisors partner with Merion? The firm will offer institutional level trading and advisory services for fixed income and a team which will do portfolio analysis and structural design for clients with $1 million or more in investable assets, said Andres.

In addition, the firm will offer a “proprietary investment selection process,” which will include new and small managers who might fly under the radar of other platforms, as well as access to insurance products through Ash Brokerage. Ash Investment Fund is also a financial backer, as is CDV Capital.

Neither firm would disclose how much money they have put into Merion, but Greg Campbell, managing partner, said CDV is “committed to fully funding the growth of the business as long as external capital is required.”

Outside capital needs should be met over six months, Campbell added. After that, he said, Merion should be able to grow on “internally generated” revenue.

Carson, which has over $2.6 billion in assets and is affiliated with LPL Financial, also plans to “self-fund” its expansion as a “rapidly growing, highly profitable enterprise,” said Jon Foster, president of Carson Wealth management Group. “It is important to note that this is not a ‘roll-up game,’” he continued. “We are looking to build a business together, not cash out advisors. It simply does not require huge capital.”

Carson is unlikely to expand beyond “a dozen or so” offices, Foster said, adding “this is all a function of opportunity. We are really looking for great like-minded partners. This is not about volume.”

The firm’s long-term goal, he explained “is to build a national, multi-location super independent. The model is to build a single brand, multi-location national firm with consistent service and offering in each location.”