As for ISO file, I really dont know, as I have very little experience using D2S to make ISO. I did a couple of times a while back, all was okay. Why you get such a small ISO with a large pulldown encoded file I really have no idea, sorry.

As for the speed, yes your right D2S with the RoBa pluggin can do a pass encode. When you inially run D2SRoBa, read all the parameters there in the first opening window. The Conditional Sizing Pass defaults are do a second encode pass (VBR) if the final output file is 2.5% undersized, 0.5% oversized or the Q value is greater than 40. If the AVI was say 1hr 50min long and 700mb in size, then the Q value will defenitely be over 40, therefore an extra VBR pass is done to get the final file size correct. If this is happening then untick that option, but expect an odd to small or to big final encode. To big can just be run through ReJig or Shrink to resize it.

As most NTSC AVI's are 23.976fps, then Pulldown will always need to be run. An alternative is to tick the NTSC to PAL option and convert them to PAL, but expect a 4% increase in playback speed (normally un-noticable). Your 100min movie will now be 96min long.