Tom,
Have another look at the schedule above, as I think 1-2 does play 4 times, and 1-4 only twice.
The 8 round problem has an interesting solution that you might want to go for:
(1 3 6 7 10) (2 4 5 8 9)
(1 4 5 8 10) (2 3 6 7 9)
(1 3 5 8 10) (2 4 6 7 9)
(2 3 5 8 9) (1 4 6 7 10)
(1 4 6 8 9) (2 3 5 7 10)
(1 4 5 7 9) (2 3 6 8 10)
(2 4 6 8 10) (1 3 5 7 9)
(1 3 6 8 9) (2 4 5 7 10)
Here 40 of the 45 possible pairings occur in exactly 4 of the fivesomes. The remaining pairings 1-2, 3-4, 5-6, 7-8, 9-10 never occur. On the face of it, not so good, but you could assign the 10 players to 5 teams of 2 and then you have a round-robin type tournament where players play 4 times with all members of opposing teams. Is that of any use?
Ian.