Any one you can get your hand on that gives you both a large and small screen (eg a Galaxy S3 and an older Sony), as well as one running 2.3 (still very common)

Any one you can get your hand on that gives you both a large and small screen (eg a Galaxy S3 and an older Sony), as well as one running 2.3 (still very common) and one on 4.2, with anything inbetween a bonus