You could try RealSmart Twixtor from www.revisionfx.com. It is a plug-in to After Effects and Combustion that will do this sort of thing. Twixtor costs $350.
A similar but more sophisticated solution is called ReTimer from www.realviz.com. ReTimer costs about $3000.
Both of these programs do pixel flow analysis and interpolate new frames from the inferred motion of pixels.
What you are trying to do is sort of difficult to start with. And you may not be able to get acceptable results with either product due to DV's compression.
But you can try the demos.
I don't know that there are any true high speed DV cameras on the market. But there are other format high speed video and film cameras. You are looking at a completely different price range from a middle-range DV camera though.
Also I assume when you did your tests you turned on frame blending in After Effects and/or Combustion.