Just FYI -- it's a bug in Wedge itself; an undefined constant. It should be defined, though, so this must execute before it's defined, or something... I don't have time to work on Wedge today, I was hoping to have an Internet connection outside where I'm supposed to be but there isn't, so I'm just saying hi while stopping by my house. I'll be back in a few hours... And might be able to fix that. In the meantime, be assured that all your posts ARE sent, they just don't show up without a page refresh.
Also, John -- not crucial or anything, but I've noticed that something like half of your plugin's JS is taken straight from Wedge's infinite scrolling code... Which isn't freely available to use anywhere. It's perfectly fine if you want the plugin to actually be core in Wedge (and I'd love for it to be), but other than that, you just can't release it with a free license. I'm supposed to 'protect' our codebase, otherwise anyone can do anything with it, and I don't want that. Not while I'm deep into the project anyway!
Oh, and to finish: I'm still undecided on whether the infinite scrolling code will use Ajax or an iframe.
iframes are good because they solve all JavaScript issues; they make it more complicated to handle form elements though (it'll mostly be with the moderation checkboxes, so I can add some code to account for them), and auto-resizing when the iframe is resized. (Most people on the net do it by, ahem, resizing after the onload event... Which is silly, because to be very precise, you'll need a setInterval to update it whenever it's needed. So if you're loading 10 pages in one go, it means that, for instance, you'll get 10 events that run on your tab, each fighting to get iframe size data. A one-second interval seems okay, but maybe not in all situations.
Ajax is good because it solves all of the iframe issues... See the pattern? :P But it also causes any JavaScript on the page to be duplicated and executed twice, which causes trouble, just look at the quick board selector which would need fixing.
I think that doing quick reply with an iframe would be best, actually, even if infinite scrolling keeps using Ajax.
But one funny thing... If you send a quick reply on page 5 when there are 10 pages in the topic, will the reply appear on page 5? If yes, if you then scroll down, and trigger infinite scrolling, you'll get your page 10 post lost between pages 5 and 6... ;)
Okay, gotta go, I'm super late...