This is a good thread. I'm not sure who are the most popular makers, but I know one thing - it's that some makers are more often on the market than others, at least without being in the business full time. I get Cutting Edge regularly, and the Henry and Scagel are nearly unheard of (except that there's a Scagel this month, available for North of $20k). Loveless in comparison are plentiful, although I realize that some model are more common than others. Right now, I don't think I would want to pay full retail for a plain vanilla Loveless drop point, from a speculator's stand point. As to Emerson, it seems that his knives come available for sale on the forums every other week or so, but I don't follow them very closely. Morans seem to be more common than Scagel & Henry, but less than Loveless. Top knives by Fogg / Kemal are nearly impossible to find - I know 'cause I'm looking really hard!
What I do note is that the 2nd hand market for "high roller" knives ($1,500 and above) is very limited on the forums. On USN, Dave Ellis has a subforum where he shows his ware, and he seems to be buying matched sets of Loveless, Emerson, etc, all the time, but he obviously doesn't get them by following the For Sale forums here or there. In fact, it's nearly impossible to find true muesum quality knives on the net, outside of dealers (but then, I'd be warry about spending $2k+ on a knife I've only seen pictures of too.)
On Swordforum, one can regularly see fully polished Howard Clark katana for sale, and those got to $3k to $6k and more, but they are the most expensive "knives" I've seen for sale on a forum.
Anyway - I'm looking forward to being at Blade, because dealers at shows do often have some high quality knives. (BTW, Les, it will be a pleasure to meet you face to face finally.)
JD