If your own corporate-branded is not specific enough, you could go with some variation on the corporate equivalent of patriotism: company spirit. From Building company spirit in multidivisional organizations by Susan Jane Goldsmith Herman, "Company spirit" is
pride in one's company, a common sense of purpose, pleasure and positive challenge in the work of the organization, security in the work environment, and the feeling of reciprocal support between members and the management of the organization
It's not the smoothest phrase, but it does show up a lot in relation to branded-clothing (especially in the custom-branding industry). For example:
Start rewarding people for showing ‘company spirit’ by taking on the brand personality and consider new uniforms that make everyone feel like part of the ‘new’ branded team.
—"Why A Coherent Brand (From Top To Bottom) Matters", MindShape.com
• More than 44 percent wear [company-branded apparel] often to show company spirit
—"New Survey Shows Employees Proudly Wearing Company-Branded Apparel: While Logo-Emblazed Clothing Used to Languish in Closets, Workers Now Say They are Proud to Have Their Jobs", Bulldog Reporter, June 24, 2010
Team Outfitters has a variety of custom packages for school and company spirit wear. Our packages range from shirts, fleece, pants and hats to promotional items.
So in your context, you could say
The cloud computing conference was full of geeks, all dressed head to toe in company spirit clothing.
I might replace "clothing" here with "gear" or "wear" (as in the last quote above), especially if you want to include things like branded lanyards and sunglasses that aren't exactly "clothing".