As their name suggests, character goods maker Cospa is one of the big players in retail cosplay items, especially replicas of the school uniforms depicted in anime. Their Cospatio label has a GJ Club summer version school uniform coming in August. As they tend to piece, the items are expensive, but pretty much top of the line.
Blouse - available in three sizes for 18,900yen ($188)
Skirt - also available in three sizes for 18,900yen ($188)
Cospa also has a Little Busters! - Rin Natsume's Cat Ears & Bell Ribbon coming in September for 2,415 yen
also a Little Busters! - Komari's Hair Accessory Set for 2,940 yen