the biggest kitchenaid with a bowl scraping paddle (called flex edge by them) is a 7 quart mixer. i would choose something bigger only if such paddle that also scrapes the side of the bowl when mixing was available. any knows if it exists? thanks : )
In response to your comment:
If you really are interested in the 12qt Hobart Mixer with the Bowl Scraper Attachment I'm sure they'll work with you to sell you one. Here's the contact information for their international sales department.
Take a good look at this video, the way the 12qt functions is the same as this monster 80qt machine.