You are right, in the Benelux, most PhD projects take at least 4 years. I know of one which took a little over 9. However, you get payed a lot more, because the new system (starting this academic year) enables the universities to draw the best students, using the paycheck as a bate (possible up to 1800 GBP a month, taxes have to be payed though, being about 40%). Germany is different there. The projects take about 3 to 5 years, and you get about 600 GBP a month (tax free).
Thanks for the info!