Not at this time for a range of frames like "1-10x0.5". Thank you for the suggestion though -- we have added it as a feature request.
As a potential workaround in the interim if this is needed functionality, one can specify the frames manually in the range field and use the simplecmd or cmdrange with the QB_FRAME_RANGE parameter (executing each frame individually). For example:
Command: render.exe -s QB_FRAME_RANGE -e QB_FRAME_RANGE -b 1 <myscenefile>
Range: 0.5,1.0,1.5,2.0
Execution: Individual Frames
Note: The QB_FRAME_NUMBER, QB_FRAME_START, and QB_FRAME_END will only specify integers at this time. The QB_FRAME_RANGE supplies the full name of the chunk, so can provide float values.