I have my AG3 mounted on rails in my R5604 and it is pretty close w/o doing any adjustments at all. I think I could get it exact with just a tiny bit of futzing around with it, but it's behind a door so I don't worry about the small stuff. I know of no fan control/temp monitor consoles that fill the whole bay unless it also incorporates a HDD adapter to fill the back and those are few and far between. The CM CoolDrive 6 is basically the AG3 with an aluminum HDD enclosure on the back, but it's about four time my price on the AG3.
One other drawback to the Rheobus is that it doesn't come with any fan extensions either. So be sure to order some if needed along with it.
That Akasa looks a lot like the original Vantec 101 with the interchangeable color panels, but those are unobtainium now - not even on eBay. No Akasas there either.
This is about the only other one that might be worth your while: Tt XController. It is pretty blingy though with diff colored LEDs on each knob for three rough temp ranges. And Xoxide seems to have the best price from a well-known reseller.
Or the Vantec NXP-205 if you have a 3.5" bay available or are willing to use a 5" bay adapter.
I see that SVC has the XController as well if you happen to be near enough to them that you could go pick it up so you won't have to add shipping.
.bh.