You know, I don't think the Arcanite transmute was especially valuable either. Even in the peak of the Arcanite Reaper, I never found a time when it was more worthwhile to do Arcanite transmutes than to do just make an Essence of Air every day. For the bulk of my character's life, I pulled at least 15g a day transmuting Undeath-->Water-->Air using my main and my 35 alt. In the past month or so, Air has plummeted, but I'm still getting 11g a day or so, minimum. And even now, it wouldn't be easy to run around in IF trying to sell transmutes for 11g. Most of the price increase due to demand seems to go straight to cost of Crystals, and have little effect on the value of the transmute.
Mooncloth is probably going to be pretty bad. My girlfriend and I both play Mages, so we have to use it for Frostfire and for crafted NR gear. She's been running two transmuters for a long time, and just got a third one, so we have a decent stash, but otherwise it would be a huge pain. Felcoth is generally not in enormous supply. The price spiked heavily when Soul Bags came out, and it's hard to see where it's settling down, but it seems to be at multiple gold apiece. Mooncloth itself is up to 25g or so.
Little trick, since most people reading this aren't from our server: make a char (level 10 Druid for TP:Moonglade is nice), and camp him at this guy:
http://wow.allakhazam.com/db/mob.html?wmob=16015
Check frequently. When he's built up a decent stash, port him out and mail away.