I found these notebooks in a local stationery store yesterday. I had never seen anything like them before and I loved them! I liked that they were different colours, I REALLY liked the tabs (I could soooo use tabs but I am too lazy to make my own), and the size was perfect.
I did not buy any so I am not sure whether they are A5 size with the tabs included, or if they are A5 size excluding the tabs, meaning that you would need an A5-wide TN cover to accommodate the tabs. Either way, they are so practical. These ones have lines but they do unruled ones as well.
Here are the specs and here is the SUCK UK site, which has some really interesting things on it!
These notebooks are also available on: