My league's tourneys last 1.5-2 hours with 8 players, and we use the same structure they use for the cheap tourneys at our local casino.
Starting Chips: T1500
15 minute blind levels:
25/25
25/50
50/100
100/200
300/600
400/800
500/1000
600/1200
1000/2000
Keep in mind that this will be a total crap-shoot and there will be very little skill involved. I use this structure because:
1. Most of the people in my league aren't willing to buy in to the more expensive tourneys at our casinos that have a better structure.
2. It gives players practice for the casino donkaments if they decide to play in them.
As players in the league build their bankrolls, I'll change the structure to match an bigger buy in tourney at our local casino.