I've never done it, but I would think approching people with that suggestion is a good idea, or running an ad in the paper. If when you go to talk to people, you had a good presentation as to how it'll help THEM, I'd think they'd go for it. Especially if you add in that you'll give them a certain amount of honey each harvest too.
There are farmers out there too that will pay you to put your hives on there property during pollinating time (heard about $25 per hive). But I think you have to move them after.....not sure.
If you have a local cooperative extention office, they might have some suggestions or leads.