Jim wrote:

I've been riding mountain bikes and would like to try road bikes for
commuting. Road bikes (mostly the narrow rims and the few spokes on
some models) look flimsy to me -- is my impression right?

Depends on the specific wheels and how well they're built. Many road
wheel configurations are strong enough for commuting.

I intend to ride in a more up-right position than those racers.
Would I look dorky when I meantion this to the salesperson doing the
fitting?

Tell them exactly what you want - a reliable, upright commuter bike.
Touring bikes come to mind (Cannondale, Fuji, Trek, etc. make
affordable models), but many types of bikes can be good commuters. In
other words, you have lots of options, and if a particular shop doesn't
want to help you, that's inexcusable and you should go someplace else.

-Vee