After reading through this thread and starting with a stock Beige G3, I went into upgrade frenzy over a period of a year or so.

I now have a beige G4 with a sonnet zif running at 400mhz, 768mb RAM and a 60gb HDD with a wings card.

I downloaded the 3ivx_d4_451 codec from macintosh garden and have been successfully capturing with Adobe Premiere 5.1 at 768x576

The resulting file size is about 1gb for 2 hours.

I have a DVD writer on the Beige G4 which I use to burn my captured data.

Its a shame the wings card can't utilise anything more than onboard video, but the 6mb of VRAM is doing its job.

I can still play DVD's using a wired4DVD card

Thanks everyone for all the tips!