The reason Smokescreen isn't lightning-fast yet is that it has to do an awful lot of work to get around the need for a Flash plug-in. According to Simon Willison (quoted on Engadget), " It runs entirely in the browser, reads in SWF binaries, unzips them (in native JS), extracts images and embedded audio and turns them in to base64 encoded data URIs, then stitches the vector graphics back together as animated SVG."
Okay, that's seriously impressive. I can't wait until it's practical, too. What do you think, DLS readers? Will it ever happen?