Somebody said it here already, the very first place to start is with the company. It shouldn't ever hurt to ask, and sometimes it just totally pays off. Also depends how nice you want it to look. Personally, I'd take it to a guy, because I can't weld well enough to be happy with it.
Also, I'm fairly new, but haven't heard of any frames disintegrating from hairline fractures. It's possible the crack is an anomaly and maybe it happened from a pothole or other knucklehead impact, and isn't necessarily going to happen again and again. Maybe start considering getting another frame body and transfer everything over? Strip and part this one out? Might take a while to sell as-is...