This is a thread that someone 5'2 started today:
http://forums.teamestrogen.com/showthread.php?t=40328
Basically - it depends on your wife. She is probably going to need something in between a 44 and 48 cm seattube - but the top tube is entirely dependent on her build.
I'm 5'1-2, I like riding about a 48 cm frame, 520-530 cm top tube, 73 degree seat angle if I can find it. I'll run about a 100 mm stem on that - seat about level with the handlebars. I don't ride wsd 'cause my torso is relatively long and my legs relatively short. However, I have a couple 5'2 friends that find my bike just stretches them out and leans them over...
You might want to consider trying her on a 48 cm jamis aurora, a 44 cm surly long haul trucker, a trek 520, maybe a surly cross check.
Kalidurga on here is about 5'2 and rides a specialized tricross - probably like a 46-48 cm one, because I fit on it.