Uh, when you were checking their website, did you notice that the most recent shots on the "Latest Images" sample page are dated June 2003, the "News and Events" link is dead, that the most recent update on the "Products" page was October 2005, that all the download links on the support page are dead, and that all the names on the contact page are the same person (Richard Chang)?
I looked up their address in Goleta on Google Maps and it still lists Megavision as one of the businesses located there, so maybe Richard is still there keeping the Megavision fires burning. But it doesn't act much like a happenin' company.
I remember noticing about a year ago that B&H Photo still listed one of their backs for sale on its website (at a mind-numbing $12,995 for a 6-megapixel back!) but just now checked and it isn't there any more.
Oddly enough, I actually do have some experience with their products: at work I have, and still occasionally use, an S3 back for our Fuji GX680 camera. It's a six-megapixel back that works only when tethered to a special interface board that goes in the PCI slot. The board only works with special Megavision software, the Mac version of which only runs under the now somewhat antique MacOS 9. (I see there's a Windows driver listed on the website, but since the link to download it is dead, it's hard to find out much about it. At one time they also made an accessory called a BatPac which allowed you to use the back without a tether; have fun looking for one!)
The Megavision software isn't too bad to use -- but the raw file format is proprietary, the user interface is non-standard, the feature set has all kinds of limitations most people wouldn't put up with nowadays, and overall the experience of using it just reminds me of how much progress digital imaging has made since 2003.
Now, if you happened to find one of these backs in an old equipment cabinet (which is exactly where I found ours) AND you had a camera that it would fit AND you happened to have an old computer that would support the interface board and software, it certainly would be worth trying out. I still use ours because sometimes six megapixels are all we need, and because it's the only way I can use the GX680 when I need extreme swings, tilts, and bellows draw.
But spend actual money to buy one? I dunno -- unless the price were utterly trivial, I'd really think hard about it.
Incidentally, if you or someone else does sniff them out and discover that Richard Chang (or someone else) is still cobbling Megavision backs together in Goleta, please post about it because I'd love to get in touch with them with a technical question or two!