I love this community, too, Cricketgrrl! You guys are so friendly and helpful!
I've been referring to the head as a "buttercup-style" so thanks, Dana and Poppyseed, for clarifying that what I like so much is actually a Stuller Solstice. I'd heard this mentioned on a few boards, but didn't quite grasp what it was referring to!
I'm very particular about the width (3mm comfort-fit), the prongs (tapered and clawed), and the position of the head (on top of the band, rather than embedded in the rim, so that it will sit flush with an eternity band). I haven't found anything that fulfilled all of these criteria, which is why I ended up thinking I would need a custom design.
Valentine, I'm not sure who LM, SK or VC are actually! I've chosen not the name the vendor because I do admire their work and I don't want to come across as complaining about them. I was just floored by the price because I've seen similar (non-designer) solitaires on their site for less than a 3rd of what they quoted me. I thought my idea was fairly simple and thus leaning on the cheaper side, but I suppose they disagree. Anyway, everyone is obsessed with them over at PS, so I'm sure they will be just fine without my business!
I will be so much more comfortable working with the vendors that have been suggested here because they are clearly familiar with moissanite and won't be snappish about working with it. (I've been shot down by a few jewelers as soon as I mentioned moissanite, and I was actually tip-toeing around that with the PS vendor, so I'm glad I won't have to worry about that anymore!)
Thanks again for your help, everyone! I'm off to check out some samples on this board.