Smaug

Just have a few questions... Is a Trail bike a must? I mean people like Hans Rey used(and maybe still do) a GT MTB. Is this a sport for people on the heavy side? Im a pretty big dude, about 100Kg but not just all fat with a old GT Avalanche LE I have trashed around on for many years now(just love the bike for MTB'ing). Its not about the money. If a trail bike is a must I buy one, because I find it very difficult to balance my bike on the back wheel but is it just me, not figured it out or is it so much harder to learn to pedal hop on a old school MTB(I feel like like my bike is old school compared too many of the new ones with long travel forks and everything)? Will I be to heavy for any wheel set or frame useable to this sport?