I guess I am wondering what sort of budget are you thinking of?
Around Boston, a place not known for low prices of anything, you can generally get a ready built 3 speed for under $250 almost any time and under $150
if you are willing to wait (I've sold a few with fenders and chain guard in the $100) range. The biggest drawback of these is that they come with steel
wheels. I can build alloy wheels, but a pair would run about $70 (making a $100 sale pretty unpractical) (27 inch allow rims can much cheaper and would
make a cheaper build).
You can of course build 700c wheels with a 3 speed hub. And put the standard northroads bars on top.