Tiffin uses residential sinks, so nothing special is needed. You just need something to fit the cut out. Sizes are pretty standard as well.
Home Depot, Lowes, and plumbing supply stores seem to be good places to start. The big box stores mentioned have a lot more sinks online than they do in the store.
Roger & Mary
2017 Winnebago Navion 24V (Sold)
2014 Tiffin Phaeton 36GH (Sold)