Choice of location will be crucial - you might be doomed to failure if the ten of you sit down in splendid isolation in the middle of a hangar-sized Mess dining room designed for 150! Is there a smaller room? Or any other slightly unusual location (within reach of the kitchens, of course)? Shame it's past the time of year for outside.
I like the idea of everyone doing a 'party piece' (also takes the heat off the Stn Cdr, who is less likely to feel he has to drone on at length from someone else's script about any leavers - no offence intended to any leavers from wherever you are, or your Stn Cdr).
The idea of guests also has potential, without turning your function into a traditional Guest Night: what about asking each of your attendees to invite a non-family guest? Of course it would put the price up, but might be a chance to entertain any civvy mates, get completely slaughtered with Service colleagues from elsewhere, embrace the spirit of Jointery as suggested above etc etc
Hope you have a fun evening, whatever you choose to do. And my fee for the above advice is an entertaining PXR posted on this forum!