I touched on Glass's two 2008 commissions as both being somewhat small scale:  Four Movements for Two Pianos and Los Paisajes del Rio (for the Philip Glass Ensemble), now with the addition of the hitherto untitled piece for Violin and Piano (recently named "Duo no.1 for Violin & Piano), which will premiere in the spring, it appears as if we are in a period of smaller scale pieces. Additionally, Glass's cello sonata "Songs & Poems" was the possible highlight of 2008 recording releases. Perhaps this is a compositional deep breath before the big operas like Kepler and the NYCO commission (and the 9th and 10th symphonies which exist promisingly on the horizon), or perhaps these pieces are simply the occasions which have presented themselves at this point in time. 
This theme carries over to the world of performances as one looks at the philipglass.com/calendar, you notice a slew of performances in the next month of smaller pieces.  Whether it's the string quartets being performed worldwide by the Smith Quartet and Brooklyn Rider, the Saxophone Quartet, or the modestly scored third symphony, there is something in the air which is suggesting elfinly scored pieces.