I bought a pair of Shimano MT22 MTB shoes about 3 years ago, and have worn them (without cleats) on several retro rides this summer, including L'Eroica.
I think they are great, they are comfortable, have a sole that is quite stiff but you can also walk in, and they lace up (rather than velcro) so they look at least reasonably retro. They are also very solid, despite three years of heavy use they are still going strong (although also smelling strong by now). With the SPDs, they also make a good spare shoe for MTB or road riding.
I don't like everything Shimano make, but I can't complain about these.