According to a report from WholeSomeGamer (via Attack of the Fanboy), they noticed that stock of PS Vita units at major retail outlets are starting to go down. Usually in this case retailers would want to restock them, so a lack of restocking would suggest that either a new model is on its way, or that it has been discontinued.
Since Sony did state that there are no plans for a PS Vita successor, the latter seems to be a possibility. In addition, the publication claims to have spoken to a Best Buy sales rep who told them that the PS Vita is no longer being stocked as it has been discontinued. A report from last week suggested that the console had been discontinued in the Netherlands, and a Sony rep did not confirm nor deny those reports.
Now the North American market is a huge one so obviously this would have a huge impact on the company, but then again we guess with more players turning to their smartphones, maybe handheld consoles aren’t really the way to go these days. In any case take it with a grain of salt but hopefully Sony will clarify the situation soon.