You got me beat (Biltmore's a year short of 20 years, IIRC, oh yesteryear.) I tried searching for RH and banks and other than a landing page re: RBS and a few quotes it was particularly light on details. RH crushed it with the RHEL and JBoss model[1] (pretty much the paragon of "ethical open-source commercialization" IMO). Are these banks replacing pSeries AIX boxes at branches, WebSphere instances for the consumer to hit, or z13 mainframes with CICS or other more-than-five-nines-accessibility with guaranteed zero data loss? (Pardon my ignorance - not a snarky quip but rather genuinely curious as to what, if any, out of the box solutions RH is pushing in that sector.)
To provide some experience I have as someone working for IBM implementing a solution which leverages docker at a large bank - no one I work with is naive enough to think that they can get away with containerising their current systems of record. Where we are significantly leveraging docker is on in-house bare metal clouds that we are using to build out middleware services.
We build all our images on top of rhel containers that have undergone hardening to meet internal + regulatory compliance. The end result is that to some extent we can say to developers "dont worry about getting your applications production ready right away, just write reasonably stable code quickly and we'll strip out all the stuff we dont trust you to do and handle it at the infrastructure level".
End result is that we can start to eliminate some of the unsuitable uses for traditional middleware systems like our datapower infrastructure that, while being great for specific use cases, is usually to difficult to work with for your average front end developer who doesnt give a damn about soap headers and broker clusters.
As far as our architecture leads are concerned, and I'm inclined to agree, docker is a great packaging format for developer outputs because it puts everything you need to run an application naked (ie no complex logging, HA, Networking etc.) Into a single versionable, reviewable, very much disposable asset. But it is not, and should not, be a replacement for proper systems of record that require any measure of stability.
[1] http://www.forentrepreneurs.com/jboss-example/