If you're into DIY, try this:
www.fittell.id.au/piezo
I had bought components for adding a magnetic pickup to the EUB I was building because, like you, I assumed piezos would sound too brittle. But once I put one of these piezos under the bridge foot I had a big, solid sound that was everything I wanted. First time I used it was a recording session direct from the DI of my Eden and it sounded huge. I still usually roll off the highs a little to remove string noise and 'clack' but the low end is great.
Like Francis said, if you want a 'real URB' sound you'll need a real URB. But an EUB can give excellent, useable sounds that have their own character. My solid-body actually works better in the blues/jazz band I use it for than a 'real' bass - I find it easier to punch through the mix. Just don't expect it to be something it's not.
Here's my EUB, a prototype by Bill Paulin:
www.fittell.id.au/eub
Bill has since made several more and refined the design somewhat since this one.