If the concern is about weight and durability, there are a
handful of vintners using aluminum bottles now.
Flasq is one producer and Jean-Charles Boisset has bottled in the past using both plastic and aluminum. Also, Coppola wines was offering product in small cans a few years ago… don't know if they are still around.
Some spirits manufacturers are also experimenting with alternatives to glass, like
this Scotch in a can. In my opinion, Scotch in a can = awesome.
If the main concern is keeping a low profile, I've always been fine using lidded plastic mugs and simply taking care to pour discretely (in the car, for example), but I suppose transporting the spirits in any number of reusable containers would work fine and might be more convenient. Those bottles from Target seem like a good idea, as long as they don't leak. One thing though, I think that most plastics will be corroded by high proof liquors… probably not a big deal for a long weekend but I wouldn't leave spirits in them for an extended period of time.
