I hate to break it to you but I don't think the 650b wheels will bring you any extra clearance on the Vagabond as the chainstays taper in a bit behind the tyre. 29x2.25ish is probably the biggest you can go. If you're Really set on something like that this guy seems to be doing it with a Bombtrack Beyond, and I think it's been done with the Soma Wolverine. Bombtrack is through axles though and it sounds like you have QR wheels?
Good luck though. I'm just going to have to live out that dream vicariously through this thread, so I'll be rooting for you.
I hate to break it to you but I don't think the 650b wheels will bring you any extra clearance on the Vagabond as the chainstays taper in a bit behind the tyre. 29x2.25ish is probably the biggest you can go. If you're Really set on something like that this guy seems to be doing it with a Bombtrack Beyond, and I think it's been done with the Soma Wolverine. Bombtrack is through axles though and it sounds like you have QR wheels?
Good luck though. I'm just going to have to live out that dream vicariously through this thread, so I'll be rooting for you.