Over here in Suffolk we play 40 overs each side in the Hunts County Sunday league. We start at 1.30, there are some late finishes, usually due to slow over rates. Format of the day is all very traditional, including 30 mins (ish) for teas. We have kicked around the idea of reducing overs to attract/keep players, but one of the problems then is how to introduce the youngsters to Senior cricket. In the 2s, we often have 3 or 4 young lads, maybe 13-16 years old. If they came into T/20 they might hardly bat, and their bowling would get hammered to all parts.
For us, I think the weekend needs to stay pretty much as is. Some days run long, but this is as much to do with having to drive fair distances - Suffolk is a big county! But half the games are at home, so it works both ways. For the hit-and-giggle guys, we have set up a small T/20 league on Weds evenings, playing against other very local villages (3-4 miles). This runs through June and July to get the light, and works very well.