There are only two companies offering overnight cruises on the Mississippi and Ohio river system:
- American Queen Steamboat Company: American Queen (paddlewheel steamboat)
- American Cruise Lines: Queen of the Mississippi (paddlewheel boat, no steam)
The American Queen had a 3 nighter last year out of Cincinnati. But for 2013 the shortest I can find is 6 days.
And to answer your question about "affordable custom cruises"... that depends on how you define "affordable"
. I´d say they are all not a bargain.
You might check the Belle of Cincinnati (out of Newport Kentucky, BBRiverboats). They did offer "overnight" cruises in the past but then you stay in a hotel for the night as they don´t have any cabins.