Well to make it even more like OTL, pull back the Crash of Black Tuesday into 1928, which unfortunately would seem to be the only possible way to get Smith into the White House. The Republicans were entrusted with continued economic growth, and if that is shaken significantly, even if it does not personally effect many individuals as of yet, they would be more than willing to consider a change in who handles economic affairs, specifically putting it into Democratic rather than Republican hands.
The above I think is what the Map would look like electorally, with changes in how people vote due to the new economic situation and how the campaigns themselves may be altered to take this into account. Considering by how much Smith lost, I can't see him winning with the sort of Mandate that Obama had in 2008 unless Hoover does something incredibly stupid and out of character.
1928 Senate Results
Republican: 47 (-1)
Democratic: 48 (+1)
Farmer-Labor: 1 (-)
My personal take on the Senate Elections. Again there isn't a wave like there was in 2008, rather there is a break in a wave that was going in the opposite direction. Rather than the Republicans picking up (8), they are losing a single seat. Many of the results were close, and considering the swing we are talking about, and how many voted straight ticket during this era, combined with the sense of unease an apparently shaky economy, the Democrats should hold their ground.
1928 House Results
Democratic: 233 (+39)
Republican: 195 (-43)
Farmer Labor: 3 (+1)
Socialist: 1 (-)
Same swing but with more seats at play and more with narrow results the swing is more visible than it is with the Senate elections. The light Green are delegations that are evenly split, and the remaining shades represent increments of (50-60), (60-80), (80-100) of that Party's delegation control. Victor Berger remaining in Office might be interesting since it also likely butterflies away his death of vehicular manslaughter by streetcar.
Although this is all just speculation and personal input on my part.