That might of been how the guy had set up his front end, eg: tilted the bars forward alot, got a longer, higher rise stem than usual. But to be honest, if you're use to bmx's, and old skool trials bikes, then a mod these days will feel completely different to what you're use to. As you can probably see, mod's have changed soooo much throughout the years. From basically being a bmx frame, with different bars and much higher gearing, to what they are today, A seatless design to give as much space possible, and just about every part is completely different to anything you'd find on any different bike! And coming back to the 24's, you will find that actually LOTS of people have them. But probably just not around your area, I think there are a big few around London. But even if you don't manage to get to have a go on one, you can probably see by video's the differences in how they are rode.