Richard - thanks for the Vireo/jacket combo suggestion. I hadn't considered that option and am still not sure how I feel about it, but it's certainly something to think about.
Doug J. - It's great to hear from someone who has used both the No Sniveller and the Ghost! From your picture, you look around my size, so the information is very much appreciated. If I end up with the Arc Specialist, I'll let you know how it goes.
Adam - The idea of making my own quilt is attractive: lower cost, just what I want, and, most importantly, a great feeling of accomplishment. However, I'm not much of a sewer, and handling high fill power down is not something that I look forward to. I hope someone can help you figure out what dimensions are right for you. Maybe you could make yourself a prototype out of some cheapy fabric first?
Douglas F. - Thanks for the info.
Don - I'm 5'11", 145lbs. It's good to hear that the Summerlite's range can be stretched.
Brett - I admire your love for Montbell's SS system! Not quite what I'm looking for, but good to remember.
Aaron - I find Ron's products to be intriguing, admire his willingness to stand firmly in the SUL camp, and always love to see small cottage comapanies. I've emailed back and forth with him and spoken to him a few times, and he has always been very pleasant. So, yes, I'd like to support his business. But... from experience, I'd have to say that I'll be quite surprised if the new Devotion bags are available in a week. I'm definitely considering the 38, but the difference between not-quite-40 and right-below-freezing is bothering me a bit. I'm just not sure that I'd be comfortable with a ~40F bag around the treeline in the Rockies, even in the summer, despite the fact that I do know what to wear to keep warm. I'm also not so sure that I'm sold on the top-bag concept. Despite the fact that the top can be somewhat unzipped and the drawstring foot can be opened, I think that a variable girth or full-zip would offer more flexibility.
Thanks all--keep 'em coming.