Not an ideal solution, but you can actually edit a copy of the dpfloat package.
If you don't want to edit the official package in your distribution, you can get a copy of the dpfloat.sty package from its CTAN page. Put a copy of the dpfloat.sty in your working directory alongside your main latex file, say mydpfloat.sty.
Open mydpfloat.sty, and look for the lines:
\ifodd\count0\global\@fpmin\maxdimen
\typeout{dpfloat moved a leftpage float from page \the\count0.}%
\fi\fi
We just need to add an \else to this. The lines become:
\ifodd\count0
\else\global\@fpmin\maxdimen
\typeout{dpfloat moved a leftpage float from page \the\count0.}%
\fi\fi
This will change the dpfloat package to consider odd pages to be on the left.
You will also need to change
\ProvidesPackage{dpfloat}[2006/10/05]
to
\ProvidesPackage{mydpfloat}[2013/04/19]
you could take a copy and change
\ifodd\count0\global\@fpmin\maxdimento\ifodd\count0 \else\global\@fpmin\maxdimenBut odd pages on the left is very strange if you are writing in an LTR language. – David Carlisle Apr 18 '13 at 22:44