Yeeee I had drop a while ago, I can still find them kickin around, albeit in the clearance sections (Or even winners!). Seems like POW and Neff are your next best bets, for sure.
Grenade is hype, too.
I know the big brands like Oakley, Dakine, and Burton make shit similar to Drop. Whatever you feel like rocking, but it seems, at least at this minute, Drop got dropped.