If you can't find an EyeTV pre-2009, their Hybrid was based on the early(2007/2008) WinTV950(non-QAM)/Pinnacle 803e. Pinnacle & WinTV had sold a Mac version in silver-white plastic case with EyeTV Lite.
As far as performance, 720p is do-able on a PowerPC G4(1Ghz) and 480(SD) stations are the smoothest for playing/time-shift/recording. Recording/time shifting 720p will slow your Mac and you can't multitask without serious audio drops.
EyeTV 3.0.2 was the last slow(867mhz-1.25ghz) PowerPC G4 supported version for Tiger & Leopard--version 4 began using different encoding/decoding codecs and minimal G4 got bumped to 1.5Ghz. Keep in mind EyeTV 3 no longer gets free web updating guide service, you're stuck doing manual scan channel guide to pull info from each station which takes ~5 minutes every 6-8 hours.
If you have a modern PC, use Media Center with an export plug-in to MP4 Video--you can tweak the codec/output to play smoothly on a PowerPC
