"Building a brand takes a huge amount of time, especially when the competition is stiff," Mayer said. "You're constrained to have a limited marketing profile, unless you have a name like Tom Ford."

Observers agreed that wealthy individuals, or midsize manufacturing-based conglomerates, are the most likely candidates to consider getting behind new designer brands.

"I would guess that the total amount invested by private equity and hedge funds in private fashion companies — whether start-ups or established players — is so small that it would not even register as a percentage of the total," Halpern said.

BNP Paribas' Morgan noted Diesel and Gibò, both Italian companies, have shown some interest in young brands with their investments in Martin Margiela and Viktor & Rolf, respectively. Other midsize manufacturers with designer brands in their stable include Marchpole (Jean-Charles de Castelbajac), Onward Kashiyama (Joseph) and Redwall Group (Alessandro Dell'Acqua), he added.

Echoing other observers, Carine Ohana, partner in Ohana & Co., a boutique mergers and acquisitions firm in Paris, said individuals or small-scale groups are probably the best hope for start-up brands. Small designer companies are typically "inefficient for the structure" of large conglomerates, difficult to integrate and possess a different culture, hierarchy and discipline, she said.

Ohana noted that historically, some "industrial groups" have had trouble integrating smaller designer brands, including Chanel, which shuttered Isaac Mizrahi in 1998, and LVMH, which sold Christian Lacroix in 2005 to Falic Group.

Still, "backers that have industry knowledge are better," she stressed.

Mallevays agreed: "A designer's main line needs to grow and be visible, but you can lose a lot of money if that segment of business is not under adult supervision."

Noting the emergence of entertainment moguls as fashion investors — consider Harvey Weinstein's recent equity stake in Halston — Burke predicted a new group of financiers geared to smaller and start-up brands is bound to emerge.

Burke noted that Ford's approach to launching a signature brand in his post-Gucci career could be a model for others to follow. Ford forged licensing pacts with beauty giant the Estée Lauder Cos. for beauty and Italy's Marcolin Group for eyewear, which generated brand awareness and royalties ahead of his apparel launch earlier this month with Ermenegildo Zegna. "Licensors are trying to pick the names for the next five years," Burke noted.