I think that Resolume should check if a DXV file is a single frame. If it is, it should show a duration parameter just like loading in a png does. This way, you would be able adjust how long a DXV file is after rendering the file (for autopilot). This would also save disk space by only saving a single frame DXV file rather than making a file to the desired length.
I know you are able to adjust the duration of a single frame DXV file by using the speed transport control, but having an actual duration in ms or seconds would be much nicer.
Another idea is to add a "single frame" or "image" option to the clip transport control drop down box. Selecting "single frame" would switch from the timeline with speed control to the same controls as loading in a png.