This Nature news article briefly mentions research by Susan Hough (USGS), Roger Bilham (Univ. of Colorado), and Jean-Philippe Avouac (CalTech) on expected fault stresses in that region: http://www.nature.com/news/major-earthquake-hits-nepal-1.17413
Searching for their most recent publications might help. It looks like Bilham is being interviewed/quoted by several media outlets.
The first Nature article reference is by Bilham 2004 (although a quick search shows there are other reviews since then): http://www.annalsofgeophysics.eu/index.php/annals/article/viewArticle/3338
Page 14, discussion section 10.2 on Himalayan recurrence interval:
"Assuming that seven to ten great ruptures permit the slip of the entire Himalayan Arc, and a recurrence interval of 500 years ( ≥ 9 m slip on 200-300 km long, 70-90 km wide, ruptures) we should anticipate M ≥ 8 earthquakes occurring every 50-70 years." That seems like a linear extrapolation based on an average slip rate of 18 mm/year plus some informed but uncertain assumptions. I don't see any specific predictive model mentioned, though.
The potential locations of future earthquakes appears moderately well described, but the timing seems really uncertain based on an incomplete historical record.
Avouac 2003 also characterizes the "where" and "how" of the "Seismic Cycle in the Nepal Himalaya", but not the "when" (large PDF, starting on p.48): http://web.gps.caltech.edu/~avouac/classes/GE277/Avouac04.pdf
(I don't know if that helps at all. Those may or may not be their best or most relevant publications, just some of the first ones that turned up in a search on those names.)