It seems lately that someone comes to this forum with that question every couple of months, and the answer is - HELL, YEAH, YOU CAN DO IT!!! You need balls of grapefruits and plenty of skill and gear to go with a well planned trip. Last weekend a group of cat sailors shoved off from Long Beach, CA to spend the weekend on Santa Catalina Island (this is an annual trip and they aren't the only ones to do it), there's the Worrell 1000 up the SE Atlantic Coast, the Texas 200, and the Philippines Hobie Challenge was just last February 16-23. Search the internet for Hobie Cat safaris / raids where you have your own Hobie in a small fleet (3-7 boats) and go island hopping in some tropical location (I did it in Thailand for my honeymoon, and my bride cried only once on the trip, so I considered it a success).
Read about these guys' adventure around Baja California -
http://hobiehawk.com/BajaAdv.html. Other mental cases have taken Hobies from Senegal across the Atlantic to Guadalupe Island in the Caribbean, from Chile around Cape Horn to Brazil, and a Hobie 18 is the first sailboat to sail the Northwest Passage.
In 1987 when I still had my first Hobie 16, I was fueling up in King City, CA and noticed an older man at the gas station towing an empty catamaran trailer so I asked him about it. He said his son set out solo from Santa Cruz on his Hobie 18 intending to sail to Malibu but didn't make it and broke up landing north of San Simeon, CA, so ole dad was coming to salvage the wreckage.
If you do go for it, keep in mind that a cat can travel a greater distance in less time than a monohull (in Thailand we did 40 miles in about 3 hours), so a 25+ mile trip can be done in no time provided the winds are favorable. My father-in-law has sailed inside the Golden Gate for 40 years on his ancient monohull and his first experience on a Hobie 16 we estimated an average speed of 18mph over 2 miles and he compared this to his top speed reached on his boat at 8 mph, so he has a new appreciation for the boats.
GO FOR IT!!!