Yes, the MSU filters are ungodly slow. If not for the smart sharpen's efficiency, I wouldn't even have given it a second look. However, I had great results using it along with the AVIsynth convolution3d filter.
As far as IVTCing with virtualdub, you have to start it on the first progressive frame (P P P I I P...) in order to make it work. Otherwise it doesn't work at all. I haven't seen any interlaced frames sneak by with this method.
No, I have not eliminated the jaggies. If you come across a good filter for this, please let me know. I haven't even begun to look for one yet.
As for the darkness of my capture, I do that intentionally in order to not lose the bright details. If you look at that first screencap in the *Official* screencaps thread, you will notice that some of the other captures are way too bright, and the details in the whites are all but gone. In capturing a little darker, I am able to retain a little of that detail. Of course this is at the cost of a little detail loss on the dark end, but I feel this is a compromise I'm willing to make - at least for this film. I'm thinking ESB and ROTJ won't need this so much.