tffy wrote:
Thanks! There isn't anything 2-cylinder available in this power range
(or perhaps less, all the way down to 60hp), is there? The a/c
performance can afford to be somewhat anemic, while mounting space is
at a premium.

The most popular 2-cylinder in this range is the 65hp Rotax 582 (and its
big brother the 75hp 618), but these are two strokes with relatively
short TBO, two things you are trying to avoid. Besides, I don't think
the aircraft 618 is made anymore.