Other current sweet spots (or close to sweet spots):
BOS-WAS night owl
Raleigh-Jacksonville
Fairly close:
CHI-Memphis (North is good, South leaves a little early)
LAX-Tucson (East works, West arrives quite a bit early)
Potential sweet spots if Amtrak had enough demand for an additional frequency and sleepers available (or maybe just coach like the Night Owl would still work). These are shifts of current schedules.
NYP-Montreal (South Montreal 10:20pm, ALB 6:15am, NYP 8:50am, North NYP 9:15pm, ALB 11:50pm Montreal 8:11am)
Carolina Overnight (South NYP 8:05pm, PHL 9:35pm, WAS 11:53pm, Raleigh 5:42am, CLT 9:12am, North: CLT 9:00pm, Raleigh 12:25am, WAS 6:29am, PHL 9:00am, NYP 10:35am. You want to keep WAS and Raleigh out of the graveyard shift. NYP would be out of the sweet spot).
NYP/PHL-PGH (West NYP 9:52pm, PHL 11:42pm, PGH 7:05am, East PGH 11:30pm, PHL 6:55am, NYP 8:50am. Ideal if hooked up to a train heading to/from CHI)
NYP-BUF/Niagara Falls (West NYP 10:15pm, ALB midnight, Buffalo Exchange 6:14am, Niagara Falls NY 7:21am, East Niagara Falls NY 10:55pm, Buffalo Exchange 11:30pm, ALB 4:50am, NYP 7:45am)
MEM-NOL (South MEM 10:50pm, NOL 7:32am, North NOL 10:45pm, MEM 7:00am. Also ideal if hooked up to a train heading to/from CHI)
CHI-MSP (North CHI 11:15pm, MSP 7:03am, South MSP Midnight, CHI 7:55am. Milwaukee would have to be in the graveyard shift)
DAL-SAS (South DAL 9:50pm, FTW 12:10am, SAS 7:55am, North SAS 11:00pm, FTW 5:58am, DAL 7:20am. Austin would have to be in the graveyard shift)
NOL-HOS (West NOL 10:00pm, HOS 7:18am, East HOS 10:10pm, NOL 7:40am. Fairly close to my Sunset Limited reschedule proposal)
SJC-LAX (South SJC 9:07pm, LAX 8:00am, North LAX 10:10pm, SJC 8:11am. Would have to leave Oakland/SAC earlier and arrive later)
LAX-Phoenix if they ever would serve Phoenix again
DAL-HOS (Roughly 7 hrs each way from old schedule for TE DAL-HOS through cars. Fairly close to my Sunset Limited reschedule proposal)
CHI-CIN would work well but it would leave IND in the graveyard shift both ways.
To me, the LAX-SJC would be by far the biggest seller. DAL-HOS and LAX-Phoenix would also be big.
Feel free to suggest others.