I actually send mine 900 miles away to Richard Photo Lab in So. Cal. I have built priority mail cost into the $50/roll processing.
The clients are told from the start that it's going to take several weeks. I'm getting no push back at all.
I'm also finding that it's not hard to sell the clients on staying under 250 shots vs 2500 shots. I help them understand how many shots they will really use and how many their freinds will actually be willing to sit through. I also suggest that if they want 1000's that video is probably a better choice than still photos.