That's not entirely accurate. The law was changed last year so that the primary alcohol in a drink (say vodka in a long island, or a single shot of anything) can contain up to 1.5 ounces of a certain alcohol. The most any drink can contain is 2.5 ounces. Previously, it was a max of 1 ounce of primary, and a total of 2.75 ounces.
You can get long islands (or any of it's billion other varieties such as long beach, etc), but the flavor will probably be off due to anywhere from 1 ounce to 1.5 ounces of primary, and anywhere from 1 ounce to 1.5 ounces of other liquors (rum, tequilla, triple sec, etc). You can mix alcohol types. You can't do sidecars, however, because that would be more than 1.5 ounces of the same primary alcohol.
It's confusing, and it really sucks explaining to patrons on a busy night.