let me preface this with a warning that I am building a frankenbike from the co-op, but I assure you that i know what i am doing with a wrench. (most of the time.)
I have an old Bianchi Boardwalk hybrid with 135mm rear spacing and I would like to put this nice rear wheel on it. it's an old Shimano 105 hub laced to a Sun ME14A rim that was previously spaced at 130mm, then I replaced the axle and spaced it at 126mm for an old Motobecane. That bike never came to fruition, so the wheel is going on the Bianchi instead.
so the question is: would it be ok to replace the axle with an axle from a 135mm spaced mtb hub, or should I re-lace the rim to a mtb hub. i have the spokes I need and I am a pretty competent wheel builder.