1920 X 1080 and 1440 x 1080 in the same sequence

You could try just making a ProRes sequence at 1920x1080 and throwing all your footage in that. Under User Preferences > Editing, check in the bottom right corner and make sure that "Always scale clip to sequence size" is checked.

On my system, throwing HDV into a 1920x1080 sequence results in the clips being scaled appropriately to fit: Scale is set to 133% and Aspect Ratio > Distort is set to -33.33. That's what should be happening.

It should be possible to work with your existing footage without transcoding (ie. playback will work and should be high quality) but you will have to render eventually.

If you shot interlaced, set your sequence to interlaced (field dominance upper, not none). Switching this at this stage can cause 50% loss of resolution.

Be careful with final export to SD DVD. If you are planning on using Compressor/DVD Studio Pro, you'll need to make sure to deinterlace when compressing the final sequence. If you use iDVD, you need to use Professional Quality for encoding, but you won't need to deinterlace. Just give iDVD your finished, HD ProRes QuickTime and it will do the rest.

ProRes 422 is a good choice for mastering. You'd de-interlace in Compressor, when converting that ProRes file into MPEG-2 SD video and AC3 audio for DVD.

You should keep the original ProRes export somewhere if you can — likely on an external hard drive. You won't need to bother making a Blu-ray image or anything else yet if you keep the original full resolution ProRes file.

To make an HD master, you can use Compressor (or Share in FCP, but it can be slower) to turn the ProRes HD file into a Blu-ray disc image, even if you don't have a burner yet. If the sequence is short you could also burn an AVCHD disc on a DVD-R with your existing SuperDrive.

Similarly, you could also give a QuickTime movie using the HDV codec to DVD Studio Pro to create an HD-DVD disc on a DVD-R. While you can only fit about 18 minutes on a single-layer disc, it will play back in HD on any recent Mac and on a (now defunct) HD-DVD player.

I think AVCHD or MP4 are your best bets to make this work. The FAT32 filesystem you'll have to use on the external hard drive could be a problem, though: it has a 4GB file size limit. A dual-layer DVD or a Blu-ray is probably your best bet for longer pieces.

http://manuals.playstation.net/document/en/ps3/current/video/filetypes.html

The alternative is to get the file to the PS3 over a network. There are a few ways to stream files to a PS3, including EyeConnect that comes with Elgato's EyeTV and the free PS3 Media Server. Let us know how you go.

As the gentleman rented the cameras, do we know what the cameras were set to shoot at?

What if one or both were set to shoot at 24p (encapsulated in 50i, do Sonys do that?).

He might need to reverse telecine his 50i?

But, I'm probably confusing the issue by even mentioning this?

Some PAL cameras that shoot progressive shoot 25p encapsulated in 50i. You can treat this footage as interlaced, which usually works until you look closely at a transition or use a speed change. Otherwise, change the field dominance to none on all the clips and the sequence and you're done. (Select all the clips and right-click to set them all or you'll be clicking a long time.)

A more modern professional camera will shoot 24p and 25p natively. In PAL lands, we rarely have to deal with reverse telecine, pulldown or anything like that. PAL DVDs, for example, are just the 24p source sped up to 25 fps.

It's likely that the rented cameras were simply set to 50i and the footage can be treated as such (at least for now) in any case.