Ordering when you get back would work great! Our plant party is September 10, and I think we've got 20 members coming so far. I'll see who else (other than Chantell, who found this thread just before me!) is interested in ordering semps.
I have a new little rock garden area, on a slight slope, where I've dumped used potting mix 4-6 inches deep and surrounded by rocks so it won't just wash away... sedums are going gangbusters there, and I think it'll be great for semps (especially bigger ones that can hold their own against the sedums?)