Another day, another issue, another "solution" ... LFF to UFF renders

Everyone who works exclusively in NTSC and/or HD probably hasn't come across this one, but this one's been a problem for a while on some of our PAL projects. I've worked out a "near enough" solution, but was wondering if anyone could think of a better one.

The issue occurs when you are dealing with DV (or DVCPRO 50) PAL material which you want to grade and render out as either Pro Res or Uncompressed. The problem is that DV/DVCPRO 50 PAL are lower field first, but PR and Uncomp PAL are upper field first, and Color does not do anything to correct the field order on the render, leaving you with field order issues when you go back to Final Cut. You can apply the shift field filter in FCP, but this means having to render the whole lot again in FCP ... it can also lead to field order problems if you want to reverse or re-time any shots (the inability of Color to handle speed changes is a blessing here, because it means you shouldn't have any non "baked in" speed changes liable to cause problems anyway).

The solution I'm proposing is to apply a translation node in the Color FX room with a vertical displacement of -1/576 (i.e. -0.00173611111 recurring), my concern is that because it is a recurring decimal, you cannot get *exactly* one line, meaning that you would expect a tiny amount of inter-field interference. However, when I compared this against using a shift-field filter in FCP (compared by using a "difference" composite, nesting, and boosting the gain) the difference seemed pretty insignificant.

Whilst this "fixes" the field order in terms of playing back smoothly, unfortunately FCP still thinks the clips are Lower Field First, meaning that it applies a shift-field filter every time you cut and paste the clips in an Upper Field first timeline. My workaround to this is to temporarily make your sequence field order "none" and leave it that way until you start rendering stuff where field order of the sequence matters (e.g. rostrum, credit rolls, etc).

So, anyone got a better way of dealing with this issue?