Alex Hirsch (The creator of Gravity Falls) has confirmed there are only two episodes left in the series.
The finale is airing in early 2016. This show is very dear to my heart, and if Avalanche doesn't take the opportunity for their soon to be best selling figures now, then they will have missed out on some major cash and fan service.
I do not understand how there has been such high demand of these figures, with even the POLLS THEMSELVES showing Gravity Falls to be a top request, and Avalanche has not jumped on this opportunity.