It is my understanding that US Aircraft has subcontracted the design of the A-67 to a Brazilian company, Geometra, formed by Ex-Embraer engineers - and that the aircraft is based on an existing design by Joseph Kovacs, who was chief engineer on the Tucano. But I have been able to track down that design, which some sources call the Kovacs K52. I have not found out much about Geometra, either, except this from Flight International:
One Brazilian SME that believes it is well positioned to leap up the supply chain is Geometra, a design consultancy with just 12 employees that started in 1998 and which has ambitions to be "the second aircraft manufacturer in Brazil", according to its president (and ex-Embraer manager) Luiz Paulo Junqueira. The company - which markets itself as offering "total management of a project from conception to certification and serialisation" - designed the wing for the (now stalled) Eviation Vantage and is in talks with US Aircraft of Akron, Ohio, developer of the A-67 Dragon.