I've found three possible alternative solutions to the "Can't Find Them 505 Blues";
1) Eddy Bauer Classic Fit
2) Wrangler Regular Fit Straight
3) Tommy Hilfinger Custom Straight
For a direct replacement, in terms of look and feel, the Eddy Bauers' are great.
The Wranglers fit OK, and are inexpensive, but some of us wore Levi's partly for the brand identity.
The Hilfinger's are a bit more dressy, with a darker tone and brighter stitching.
This was determined by an afternoon of visiting the local outlet mall and just trying things on until I found some that "felt" right. (My size is 34 x 34.)