I know you're looking for standards to stock. But I love a good surprise! The last time I was at the feed store, they had a few frizzles, but I hadn't seen them before and they didn't have them today. I happened to ask if they every get silkies in (which I've NEVER seen there) and was told they do from time to time. I asked the clerk to look up when the next shipment is due in; if they come, it will be Tuesday! Guess where I'll be? I have all the chickens I was planning on - all of their "normal" stock - but I'll make room for something I unusual - or 2 or 3.
BTW, I can't find silkies round here. Maybe I'm not looking in the right areas. The couple I've found on craigslist are so overpriced I could get half-dozen of the 'common' breeds for the price of one.