i'm no poulenc scholar (but happen to love many of his pieces). i've got a book here (roeder's history of the piano concerto) and on page 362 it says:
"poulenc, a gifted pianist, composed five concertante works, all featuring keyboard instruments - piano in three, organ and harpsichord in one each. the earliest, for harpsichord, is probably the most obviously based upon neo-classical models. the 'concert champetre' (pastoral concerto) for harpsichord and orchestra was inspired by a great harpsichordist of the first part of this century, wanda landowska."
reading on, poulenc said it was she who "fired his interest in the music of the seventeenth and eighteenth-century french masters." she played his concert champetre in october 1928 and poulenc accompanied her with an orchestral reduction on the piano!
his 'aubade: concerto choreographique' was for piano and an orchestra of eighteen instruments. "it was conceived as a ballet to feature, simultaneously, a dancer and a pianist. nijinsky created the original choreography to the story written by poulenc." (i don't know the story - maybe will check into it). anyway...then there's the more traditional
concerto in D minor for two pianos and orchestra (1932) and is one of the composer's most widely heard compositions. poulenc and his boyhood friend jacques fevrier played the first performance. "the pianos play throughout the work, frequently alone, but they are rarely given truly virtuosic display material." it hints at prokofiev's lyricism. there is also an element of balinese music in the coda of the first movement.
then there's the organ concerto (skipping this since we're talking piano) and also his last piano concerto which was commissioned by the Boston symphony orchestra for poulenc's 1949 tour with singer pierre bernac. this has three mvements. reflect poulenc's late serious style, relies on strings a lot, and uses light-hearted, thematic material in the last movement of the concerto (you can hear strains of stephen foster's 'old folks at home' and offenbach's cancan tune - and various tango related rhythms). there is not a lot of solo virtuosic playing for the piano, though.