N. spec. B in Clarke's "Nepenthes of Sumatra and Peninsular Malaysia" has been officially described as N. izumiae. The description from Charles Clarke, Troy Davis (fatboy) and Rusjdi Tamin was published in Blumea 48, No.1, 2003, p. 179-182.
For those of you trying to get a copy of this article should also look for Blumea 47, No. 3, 2002 p.537-540. A. Schuiteman and E. F. de Vogel describe N. vogelii in this issue.