Here's some places where our group ended up booking...
Menorca (near airport)
http://tinyurl.com/pzw963
We're giving apartamentos binicudi a shot (35 euro/night)
Menorca (near Ciudadella)
Hostal Mar Blava / Cala Bona
http://tinyurl.com/plwane
40 euro/night, 5 min walk to town centre.
Some friends booked Apartamentos Roc Oasis Park, think it was 28 euro.
Barcelona
http://www.anasguesthouse.com/
38 euros per person. In the Eixample district.
http://www.barcelonaforrent.com/