At the risk of outraging everyone, I'll offer another point of view...
As has been suggested, this type of rebranding practice is common. The economics literature refers to it as a form of price discrimination. When you have two types of consumers (think of them as ones who are rich and brand conscious, and others who are less wealthy and driven to seek high "value"), it is natural for the seller to try to satisfy both groups' demands simultaneously by creating two distinct products and selling them at distinct prices. Here, we see the seller satisfying the desires of those seeking an ostentatious brand, while simultaneously satisfying those who seek "value" by offering the same product in different clothes. This is good news, as it leads to a greater number of people being satisfied.
Obviously, the payoff for the seller is that he gets more revenue. But it's also good news for the "value" shopper. If the manufacturer is covering a great proportion of fixed and R&D costs when selling the Lexicon brand, then he is able to sell the down-market brand with a lower margin. So, while the Lexicon consumers seem to get screwed, the Oppo consumers are actually better off. Does this practice seem so heinous now? I guess it depends who you are. Without the Lexicon marketing effort, Oppo players would likely be costing everyone else significantly more.
I think people here have the tendency to be outraged in this scenario because it calls into question the sense behind our whole audiophile mentality. Here is evidence that "audiophiles" aren't savvy enough to judge a product on the sound quality it produces. Surely a manufacturer who sells a single product at two wildly different prices should expect to sell very little of the expensive product: any fool with ears will recognize that the extra $2500 for the Lexicon simply isn't buying any improvement in sound quality. Apparently, that doesn't work in the audio world because not enough of us are smart enough to know what we're getting for our dollar.
Chad