I believe this is just another work from the mangaka which had nothing to do with Needless. Though the 2 girls did resemble Mio and Setsuna.
http://www.mangaupdates.com/series.html?id=12201
On the correction, the [Black Spot] doujin is 330 pages long while the prototype Needless 1 and 2 are 2000 pages long altogether. A 2000 page book would be
super long in length and near impossible to publish.