4 hour shows were the rule for me since the '70s, though early '90s we picked up a once-a-month 5-hour show at the original Dick's Last Resort in Dallas where pay was higher than normal. That one lasted 7 years.
Playing 3 hour shows as a rule these days, nicer rooms, pay scale is roughly double what the 4 hour bars pay/paid.
Still doing a weekly 4-hour Tues jam host gig for the old $100/man scale + tips. It's saving graces are it's off-night work and outside of the first set, I usually don't have to play the whole night. (North Texas TB'ers PLEASE come sit in Tuesday nights at The Cottage Lounge in Dallas - help a brutha out!)
Only experience I've had with multi-band shows over the past 20 years been at either festivals, special venue events or benefits for worthy causes. The festivals have paid $200/man, special venue events have paid standard Fri/Sat night scale.