1. Your outstanding question is about why you have more than one *.wim file and how did it get there?
2. Your Toshiba image is on a separate partition and your multiple *.wim file scenario occurred on the %systemdrive%\Recovery folder?
In regards to why someone would create a custom recovery - to me this seems obvious, customisation. I suppose, for all the same reasons that we create slipstreamed OS install disks, just to make the final release closer to our individual environments. I can see the benefits for many companies of doing this. For example creating multilingual images or adding more than one image to the same *.wim file, injecting drivers
and updates into the *.wim file. But as you said you haven't been near that, so'll we'll cross that off the list.
You said...If you get a chance, could you check your Recovery folder and see if you have more than one sub-folder there.
I really wish I could, I want to now the answer too; but I can't check my recovery folder for you at the moment. I'm in the process of an international move and my WIndows 7 machine is on a ship in transit to my new address. I'm on my XP netbook. Hopefully someone else will read this and chip in. (I've highlighted the question and reposted to help us here).
A side thought - you didn't use the Windows Automated Installation Kit (WAIK) did you? It contains IMAGEX that is used to create and modify *.Wim files. I thought it's worth bringing up and ticking off as well.
Given that you've been through all I've suggested previously, I've shot a quick note off to the Microsoft Recovery Environment team, I'll let you know when I hear back from them. In the interim, lets hope that someone checks their recovery folder and lets us know the contents. I also want to find out the pre-installation Environment might have a play in creating another *.wim and if repairing your installation builds another.
I've had a bit of a search since our last conversation. There's really not much info out there that focus on the specifics behind WinRE and recovery *.wim files. I don't like to assume based on web generic info. I like nice little Microsoft issued white papers that tell me 100% what is going on. So fingers crossed that we an official response. No doubt we'll all be the-wiser after this.