My solution at the moment: Import photos using no name in projects, Aperture splits anyway,
How are your "Impert Preference" settings and "Import Settings"?
In the Aperture -> Preferences -> Import set the "Split Projects" Selector to the longest possible value, two weeks.
And don't drag projects from the Finder, select them in In the "Import" Panel;
make sure you have all import options visible by enabling them in the "Import Settings" drop down, then uncheck: "Automatically split Projects" in the "Aperture Library Brick"
I also have my Aperture library setup by date. I do this with an Applescript that runs once the images are imported into Aperture which places the images in projects named by date in Year/month flolders.
See this thread convert projects to folders for more information.
Post back if you have any questions,