I was wondering if anybody knows of an aftermarket swingarm for a 250EX that is a little bit longer than stock?

 

It'll be a bit before there is anything like a bolt on long swingarm available for the 250ex. You see it goes beyond 'Gump' grade machining/engineering to make a simple bolt on 'longer shaft drive.' Also if they are ever available the price isn't likely to be competetive with the simple design of a miniture tube ladder with a bearing carrier at the end.