SGP: Search - Forerunner or "Universal" Symbol

[ColdGlider]

It would almost be a travesty if we cannot find this image in ODST: http://halo.wikia.com/wiki/File:Fr_universal_symbol.png

Since it is linked with Forerunner structures, perhaps we should look on the Data Hive level at the SI construct.  If we found it, we'd also have more confidence that the SI is the byproduct of the forerunners; furthermore, it would be more support of the concept that ONI was aware of the Forerunners prior to the discovery of the first Halo ring (which I think is implied or stated in the books somewhere.)

[MajorDeal]

While I'm not certain that the SI is a forerunner construct, you are correct that this, or a similar marathon-like symbol has appeared in every other Halo game so far. There are way too many to list, but here are just a few examples off the top of my head:
Halo CE: On The Pillar of Autumn and on Capt. Keyes' pipe.
Halo 2: On doors on the levels "Regret", "Uprising", and "Great Journey".
Halo 3: In the terminals (image noted by ColdGlider above) and on the control panels of the elevators in the level "The Covenant".
I haven't seen a similar symbol in-game in ODST yet (allowing you to use this as an emblem for your firefight character doesn't seem like it counts), but I am going to be on the lookout for it now.

[Atarigen]

Very interesting. The second image is the Janus key from Spartan Ops. The links speak of other symbols on the Elite. Does anyone have shots of them?

[ColdGlider]

Very interesting. The second image is the Janus key from Spartan Ops. The links speak of other symbols on the Elite. Does anyone have shots of them?

What "second image"?
What "links"?

When referencing something, please be specific!  (Especially since this is a major necropost.)  Adding a link to what you're talking about is always helpful!

[Atarigen]

 I am talking about the image described here as an interesting discovery. http://halo.wikia.com/wiki/Talk:Forerunner_symbols

 It appears to resemble a Janus key. http://halo.wikia.com/wiki/File:Janus_Key-Red.png

[Scatcycle]

Seems like quite a bit of a stretch, especially considering how the first symbol is mainly curved and the key is mainly straight lines.