Would a 1W Amber SE be bright enough?

[NightShift]

...in this turn signal? pic

Figuring since the lens is clear and all light would go right through.

Seems like it would be hard to mount one in a 3157 bulb...haven't tried yet.

[highlandsun]

Mebbe you should wait for the 2W Luxeons to come out...

To meet SAE specs you need at least 96 lumens. You should build in some excess capacity (10% or so) to accomodate the normal degradation of light output over time.

The HighDome/Lambertians are the brightest. You're still going to need more than one LS though. Too bad there aren't any 5W ambers, that would be perfect for your lamp.