The original rumor has been updated with this statement:
item removed as source could not be confirmed)
Translation quoted from Magic Box:
RUMOR: Japanese newspaper Tokyo Keizai reported a rumor that Sony is set to reveal a new PS Vita model in September before the Tokyo Game Show. The new model PCH-2000 will have a 6.3" display manufactured by Samsung (screen size of the current model is 5"), and the resolution will remain at 960 x 554 pixels. The amount of RAM will increase from 512MB to 1GB, to allow more programs to run in the background, the amount of RAM used by games will be unchanged (meaning games are still compatible between old and new models). In addition, the design of the new model will be more in-line with the PS4 design; and the system will launch with new game titles.