I remember doing this as a kid... You know, for those with kids, its actually pretty fun to do it with a coffee can (can you get coffee cans here in the UK???)- and they can roll it back and forth between each other- putting in marbles, closepins etc- acts like a dasher, which helps in the mixing process.
We made ice cream this way too- Taking a smaller can, putting in the custard, or cream, sugar, etc- sealing it- then putting in a coffee can with ice and rock salt and rolling it back and forth...
I may try again to make my own butter- but since it seems that you can do it with a mixer- I may try it with the kitchen aid stand mixer and see if it works.