I have created the Mississippi class Runabout from star trek renaissance, which i've only seen online, i presume it isn't canon. This is the largest runabout I've made so far, breaking the 1000 block barrier. To my knowledge this is the smallest thing capable of a "saucer separation" in it's own canon. This Runabout is usually found on large ships or star bases.

This Runabout features a landing gear system with 3 legs, it has the usual homely features expected in a runabout and a juke box. the shuttle sleeps 2, but has numerous seats for passengers.

This runabout works with Zeppelin mod, as per usual. Though i have to admit, this one REALLY is close to the limit with it, so don't put too many extra blocks on there. Enjoy