Searched for Thomas Stephens in one of the Waterloo University libraries, and found a tiny note in a French encyclopedia, whose name I forget now. The note dealt solely with Stephens' letter to his father regarding his voyage to India.
In the New York Public Library, instead, I browsed through several collections regarding rare and ancient books and manuscripts - in the UK, in Europe, in the US - but not in Portugal, unfortunately. Of course, most of the time only the collections are listed, and not the holdings in each collection. And then there is the problem of the name: the variations of Stephens' name are enormous. I found, in Graesse, the following: Thomas Estevano; Thomas Estienne de Buston; Thomas Estienne de Buten. These were new to me, except for the first.
More interestingly, I discovered a new edition of the Dictionary of National Biography: The Oxford Dictionary of National Biography. Like the former, the latter also contains an article on Thomas Stephens. But the former was by A.F. Pollard, with its famous mention of having seen the three printed editions in the Archivo Universal in Braga, Portugal. The latter instead contains a new piece on TS, this time by our very own Charles Borges, formerly SJ, and now teaching at ... some Jesuit University in the US. Not much on the Khristapurana, though.
Nelson Falcao's publication of this doctoral dissertation has, instead, found its way into the NY Public Library.
The facilities that these people have: enviable!
I could spend weeks there.