Wow, I just realized that one of the segments on Silversea's 2008 World Cruise goes from San Diego to Honolulu:

30 Jan 2008 Wed San Diego, California
31 Jan 2008 Thu Ensenada, Mexico
01 Feb 2008 Fri DAY AT SEA
02 Feb 2008 Sat DAY AT SEA
03 Feb 2008 Sun DAY AT SEA
04 Feb 2008 Mon DAY AT SEA
05 Feb 2008 Tue DAY AT SEA
06 Feb 2008 Wed Hilo
07 Feb 2008 Thu Kailua
08 Feb 2008 Fri Honolulu

And it's only 9 nights, which would be doable for us "working stiffs". AND, Greg's birthday happens to fall during that timeframe...

Hmmm...intriguing!