Personally, everytime I see someone posting nebulously about a 650B conversion for "wide tires" I automatically assume they actually mean:
"I want those awesome Panaracer Hetre Tires and I am willing to build a set of wheels just so I can use them"....but don't actually come out and say it because internet forum rules dictate that you never make a definitive statement unless you want to have someone nitpick it apart.
I am currently building a set of 650B wheels for the Hetres I bought 6 months ago. The only reason I am building these wheels is to ride Hetres. I'm hoping it will all fit in the Frame I've picked.