Platinum Games executive director Atsushi Inaba has expressed his admiration for Nintendo's 3DS console in a recent interview with The Verge, but has also added that the company has too many ongoing projects to fund development for a 3DS game at present.
We are very interested in the Nintendo 3DS as a platform. I view 3DS as a proper, straightforward evolution from a platform that has had huge success. Being able to view stereoscopic 3D with the naked eye is a great innovation, but very straightforward, so I'm very interested in it.
Currently we have a lot of titles in development, and we can't fund a 3DS game ourselves. So there's nothing in the works. But I'm very positive on it.
Platinum's previous handheld title was Infinite Space on the DS, released in Japan way back in 2009 and in the West the following year.