Half jacket - eye jacket
Half wire - Razr Wire
Scar - Valve...
Minute - XX

Anyone has anything more to add?

The XX X-metal is a bigger version of the Juliet

monster dog - monster doggle

Dartboard - Dartboard L

Zero - Zero s - Zero L

Mag Switch - Mag four - Mag four s

The list is endless if you take into account generations like Racing Jacket and such...

racing jacket - water jacket?

well oakley should try to create more new designs if possible...

Romeo - Romeo II...oh wait....

In terms of looks:

Mars - Moon
Switch - Splice
Eye Jacket 3.0 - Half Jacket - New M Frame
Old M Frame - Sub Zero
Gascan - Duncan (Fox Eyewear) hmmm, both end in -can, just noticed that

I always thought [in terms of possibly related/similar styles across all styles and materials]

Twenty (XX) - Juliet

E-Wire (original)- Eye Jacket - Zero 0.4

Square Wire (original)- Straight Jacket

OAKLEY ; OAKLEY
OAKLEY ; OAKLEY

it is all about their perception of style

Romeo: http://www.o-review.com/glassesdetail.asp?ID=170

Eye Jacket 3.0: http://www.o-review.com/glassesdetail.asp?ID=63

I can think of many, but one really sticks out to me as being a remake of the other:

A Wire(Original with false Hammer earstems)

Whisker(remake of previous stated style, this time with actual metal Hammer earstems)

Old blade - New Blade!
Eyejacket - Eye Trenchcoat
OTT - Why 3 lens 2...wait, those aren't very similar are they?
Actually the OTT is kind of a big, mutated Moon
Ten's - Gen 3 Frogskins
Warden - Crosshair

Wow the Romeos and EJ 3.0s do have similarities... especially in the lens shape

except EJ3s were uuuugly =P

I was just on O.com looking at x-metals and noticed for the first time (I hardly ever go their anymore since finding o-review) that with the mars and romeo gone, 3 out of the 4 x-metals available are (stylistically) just the same frame with taller orbitals. From big to small, penny, juliet, xx (if you discount the SH on the penny).

I know that is old news but just as I spotted the similarity between the EJ 3.0 and the original romeo, i see some major similarities between the e-wire 2.1 and the romeo 2.

E-wire 2.1:

http://www.o-review.com/glassesdetail.asp?ID=458

Romeo II:

http://www.o-review.com/glassesdetail.asp?ID=1091

I know there are only so many things you can do with the shape of a frame but it still makes you think.