Probably come from the same factory and the same production line as the PBSF. Its made in China also and the Chinese rarely abide by our patent laws if ever so andwho knows if PB has a patent so they will make it and put your name on it like another poster wrote above. Once the patent expires its a free for all just like on the Temper Pedic mattresses so now you see the clones being sold at Costco and who knows where else.
Its possible, but whats more likely is that some manufacturer presented working prototypes to several suppliers in China and asked for bids and samples and rejected some based on QC issues in the samples. The contract was then awarded to one company, but since the company (or companies) that were turned down already had the details - they decided to capitalize on the situation anyway and direct market similar products. I know of at least a couple situations where that not only happened - the 'counterfeiters' went so far as to steal the photos and description from the website of the ligitimate product in an effort to dupe the public into believing they were getting the same thing.
The Chinese government has received a lot of criticism for Internet censorship - ie blocking a long list of Internet sites. Interestingly enough - the sites they regularly try to restrict access to are the sites most commonly used to sell counterfeit merchandise, pornograpy, Internet gambling and bootleged movies and music. Maybe its not so much censorship as an effort to deny organized crime yet another avenue of influence - one that currently has no international customs personnel to answer to.
I ordered four from dealextreme, mostly out of curiosity. After two weeks shipping they appear to be very similar to the ebay/flimsy gasket version. The clear tape trick sounds like the most sensible solution. As near as I can tell if they'd used slightly thicker gasket material these would pass muster. I guess you get what you pay for.