Ruger has been done multiple specialty cartridges and configurations in LCR's, SP101's, GP100's, and Redhawks - even the Super Blackhawks got a boost with the 454 & 480 offering, the Single 6 got a revamp into Single 7... However, despite all of this variety in the other revolver product lines, Ruger really hasn't done squat for the Super Redhawk - the "Exclusive Models" were a 7.5" 44mag with nothing different except a fiber optic sight, and the 5.5" 454C Toklat.
So why a 10mm? Well, the 10mm tide seems to be coming back in lately (as much as it ever does), and it doesn't require any significantly expensive redesign of the revolver, just different reamers and a new barrel. We KNOW if Ruger would have done a 10mm GP100, they'd have gone 'safe' and done a 5 shot version like the 44 Special, and even at that, I'm prone to think Ruger is a bit too risk averse to take on the other implications... And again - they already have a few specialty GP100's on the market.
That's my opinion on the matter. Ruger was scratching their heads and trying to think of what they could do in the SRH to keep the product line alive - the Toklat received a luke warm reception, so I don't think there's been a lot of drive to re-release it in 44mag or 480... I'm sure there was a marketing & product development meeting where they sat around and said - "well, that didn't work, so now what else could we do with the SRH to spice it up?" And whichever employee who pushed the 10mm SR1911 (which seems to be doing well with market interest so far), likely stood up and said, "well, what about a 10mm?"
