Hi nazcalines, with a bit more information we could give better advice. Have you done all the measurements to figure out if it is feasible to convert your Univega to 650B? Brake reach, clearance between chainstays and fork blades, etc? What about clearance for fenders? I think the 650B google user group (just google that) has a helpful spreadsheet of actual tire widths on different rims.

Many 650B people (myself included) use wheels built with Velocity Synergy rims.