Well at present the 8 stone are as follows:
Bronze Ioun Stone (Mana +5%, Mana Regen +5%)
Dusty Rose Ioun Stone (Defense +50)
Golden Ioun Stone (Mana +15%, Mana Regen +15%)
Lavender Ioun Stone (Defense +25, Resist All +10%)
Obsidian Ioun Stone (Vitality +5%)
Pale Green Ioun Stone (Health +10%, Attack Rating +5%)
Pearly White Ioun Stone (Replenish Life +5)
Silver Ioun Stone (Mana +10%, Mana Regen +10%)
I'm open to suggestions for values and/or level requirements but just remember that most per level modifiers are measured in eighths so all units per level need to be measured in 1/8, 1/4, 1/2 or actual integers.
[edit]
Well apparently that just sent everyone who wasn't already working on something for PH running and screaming
Here's a jump start to get the cogs turning:
2 per level = 20 at level 10, 40 at level 20, 80 at level 40, 120 at level 60, 180 at level 90
1 3/4 per level = 18 at level 10, 35 at level 20, 70 at level 40, 105 at level 60, 158 at level 90
1 1/2 per level = 15 at level 10, 30 at level 20, 60 at level 40, 90 at level 60, 135 at level 90
1 1/4 per level = 13 at level 10, 25 at level 20, 50 at level 40, 75 at level 60, 113 at level 90
1 per level = 10 at level 10, 20 at level 20, 40 at level 40, 60 at level 60, 90 at level 90
1/2 per level = 5 at level 10, 10 at level 20, 20 at level 40, 30 at level 60, 45 at level 90
1/4 per level = 3 at level 10, 5 at level 20, 10 at level 40, 15 at level 60, 23 at level 90
1/8 per level = 1 at level 10, 2 at level 20, 5 at level 40, 7 at level 60, 11 at level 90
If you want me to miss you, you have to GO AWAY first...