I don't know where all this talk about LG is coming from. Let me try and bust some myths here...
Myth #1. Google will choose a different company for each Nexus.
I don't think anyone at Google has ever stated this specifically, if so please post a link. There have only been two Nexus phones so far so not really anything to go by, although if you think about it, the HTC G1 and later the HTC Magic were each the developer phone for Android for a period of time before they did the Nexus One, so if we're looking for patterns, I don't really see anything that says Google avoids partnering with the same company.
Myth #2. Samsung doesn't/wouldn't use a Texus Instruments processor.
This is irrelevant for two reasons...
A.) Although Samsung does make their own chips that is an entirely separate division of the company, the part of Samsung that makes phones actually chooses which chips to use between a number of chipmakers just like any other manufacturer, and if they decide to use Samsung chips they actually have to bid against other companies to get those chips. And although Samsung hasn't had a record of using Texas Instruments chips specifically, this pretty much means nothing because they certainly don't have a record of continuously using any one chipmaker. They've recently used Tegra 2 in the new Galaxy Tabs and in some versions of the Galaxy S II, and even a Qualcomm Snapdragon in the upcoming Samsung Hercules (T-Mobile's Galaxy S II), so I see no reason why TI means it couldn't be Samsung.
B.) Google chooses which processor is going to be the reference platform for a given software release, which is going to be Texas Instruments for Ice Cream Sandwich just like they chose Tegra 2 for Honeycomb. Have you noticed how pretty much all the Honeycomb tablets run on Tegra 2? There is a reason for that. Also, Google chooses the processor in the Nexus devices, not the manufacturer. Do you think that Samsung would turn down the opportunity to make the next Nexus because TI was chosen as the reference platform? I seriously doubt that. And if we're looking for patterns, as I've already stated they used Tegra 2 in the Galaxy Tab even after Exynos was available simply because Tegra 2 was the reference platform for Honeycomb, so if anything they at least have a record of going with the reference platform.
I remember the rumors of LG possibly being the next manufacturer way back when Andy Rubin talked about a Nexus 3, but there was no evidence, just as right now it seems all the rumors popping up again of LG are based around TI being chosen as the reference platform, which doesn't really mean anything as far as this is concerned. The only thing we really have right now is Phil's source that says Samsung will be the manufacturer, and obviously no one really knows for sure yet, but until new evidence arises that says otherwise, this is all we have to go by.