I'm going to begin working on a big project about 90 minutes long. I've got primarily HDV footage, so I'd like to edit it on an HDV timeline. However, about a quarter of my footage is in 16:9 DV, and I'd like to just throw it on the HDV timeline, and when I'm done, make an HDV 1080i60 render, and an SD 16:9 MPEG2 for DVD. Will I encounter any problems with the field order difference? I remember hearing somewhere on these forums that FCP 5.1 would screw up the DV to HDV back to DV conversion, but I couldn't find it. I'd really prefer to edit in HDV, but I suppose I could downconvert and edit in DV if it's really necessary.

better still would be to edit in a "proper" editing codec such as dvcpro hd.
alternatively now might be a very good time to invest in the FCS2 upgrade ... FCP6's open format timeline will make this a no brainer