An iPod is just a small, portable hard drive with some software installed to manage music files. What the output of the iPod sounds like depends completely on the fidelity of the bits you put on the hard drive and what you choose to do with them as they come off the hard drive.
If you play mp3 files ripped at low bit rates through the headphone jack you're going to get low-fi, or maybe mid-fi, depending on the bit rate and your own standards for reproduction.
If you play lossless files through the line-out connection, then through an external DAC with good jitter control, most people would certainly consider what they're hearing hi-fi.
The point is that your question is impossible to answer because it makes the same sense as asking the question, "Is a speaker hi-fi?"
