Hi,
As I recall at around the same time that this so-called "screen shot" turned up, an OS/2 port of the BOCHS 386 emulator turned up around the same time. It was slow and painful to run even on the fastest processors available at the time, but you could install (if you were patient enough) a full copy of Windows 95 on it similar to how you can install Win95 on Virtualbox today.
There was speculation at the time that this "IBM emulator" was simply a screen shot of BOCHS with Windows 95 running which someone had tweaked a bit. It is anyone's guess if this was actually done inside IBM or if it was someone who just decided to have some fun. With the lack of anything other then a screen shot it is all speculation, but it would not surprise me to hear that someone inside IBM might have looked at this.
At the time of Windows 95's release I suspect there was a lot of discussion within IBM about OS/2 - while Lou Gerstner may have already made up his mind, there was also momentum behind OS/2 - the Just Add Warp marketing campaign - aimed at home users - was released in the fall of '95, resulting in December 1995 with OS/2 having more sales then Windows 95 had to home users (ie, I'm not talking about pre-installed on new PCs. but rather people going to the store and purchasing the OS). Then early 96 - with the PowerPC version still not being completed (although they had "shipped" a version to select customers in December '95) - this was a huge part in the decision (recall that back in those days IBM still thought the PowerPC chip was going to be the next big thing!). From what we know of the Power PC port of OS/2, it was a strange beast. From what I recall it could run Dos and Windows software without modification, but in order to run OS/2 applications - the apps would need to be recompiled from source. And many parts of it were still very much "beta" level code.
If I recall correctly there was also some discussion around a comment that one of the IBM developers had made surrounding the win32s driver (the driver that allows win32s 1.25 to run in WinOS/2). The discussion had something to do with the driver having the capability to be modified / extended to allow other 32 bit code to run within the OS/2 Dosbox sub-system. Some speculated that this might be a route for Win95 to be able to function within OS/2, although my own suspicion is that it was more in reference to the fact that Win32s version 1.3 had been released by Microsoft, and IBM wanted the potential to support this within WinOS/2.
Cheers!