In reply to riff156:
We've stayed at both of these in the past - usually two beds, occasionally 3, and very good and at reasonable prices:
Tina's studios, opposite the Aegean restaurant:
http://www.booking.com/hotel/gr/tina-studios-kalumnos.en-gb.html?aid=311076...
(Tina used to have her own website but it seems to be down at the moment, but its now on booking.com)
Hotel Acropolis Apartments: bov the gift shop in the middle of Massouri:
http://www.booking.com/hotel/gr/acropolis-masouri.en-gb.html?aid=318615;lab...
We had a bad experience at Appolonia Hotel Apartments one year - no hot water for 5 days and endless promises of sorting it out.
If you search the forums for Kalymnos Accommodation you'll get more recommendations than these.
Good luck
Dave