Ickleton as an area is a possibility, though most of the new build houses seem to have tiny gardens (that one Tingalingle linked seems to just have a bit of gravel, despite the sweeping countryside views
). Ickleton seems to be bang on the M11 though - does it get a lot of traffic noise? I noticed a bit of traffic noise when I was pootling around Whittlesford, and that's a good distance further away from the motorway.
Great/Little Shelford and Stapleford are on my "would love to buy in" list, but there's hardly anything on offer around there at the moment. Watching Zoopla and Rightmove like a hawk, though. 
Okay! Since you lovely folks are veritable founts of local information, let me tell you the current list of villages I'm considering, based on distance to Harston and primary school catchment area:
(deep breath)
Coton, Highfields Caldecote, Toft, Comberton, Bourn, Kingsdon, Great/Little Eversden, Harston, Orwell, Barrington, Shepreth, Foxton, Newton, Thriplow, Fowlmere, Meldreth, Whaddon, Bassingbourn, Litlington, Barley, Great Chishill, Chrishall, Heydon, Great Chesterford, Linton, Abington, Babraham, Whittlesford, Great/Little Shelford and Stapleford.
Can anyone weigh in on which ones have at least a shop or two? Any villages particularly nice or grim?