Through the Finnish running forum I found a Jim2's running page which seems to have a lot of useful information. The Ultimate Speed Workout is... simply a 10k race.
So the idea was to warm up for 1k, and then run properly for 10k at around 5:20 pace, which is slightly faster than last weekends Forssa half-marathon pace of 5:32/km. That was probably a bit optimistic, as it felt like serious work up to around 5k, after which some kind of runners-high sets in, calves, legs and everything relax and settle in on the pace while kilometers 6, 7, and 8 fly by much faster than the planned 5:20. After that it's a struggle again for km 9, and I decided 8 fast kilometers were enough...
