I've been listening to The Streets of New York and last night I paid my five buck$ to Concord and downloaded a two-week perusal of the score. It looks like great fun for the two pianists, but it is VERY busy and there is LOTS of music in this thing. And the vocal music requires good ... you know ... singers. Oh my. The two-piano and vocal book is 310 pages long, and I am here to tell you it is full of notes.
Piano I doubles on celeste and Piano II doubles on accordion. It would be nice if my choice for the second pianist happens to play accordion, but all of this can be done on keyboards if the patches are of good quality. This will be performed in the same space as our I Do! I Do!, so it's absolutely two keyboards, not pianos. And even if we had the space for it, no one around here has a real celesta except the symphony orchestras, to my knowledge.