I've changed the name of AceCast to RapidCast just to avoid the "Ace" prefix in the addon name.
At the same time, I added initial eCastingBar support.
This addon works with blizzard's standard casting bar, Pitbull's player casting bar, eCastingBar, oCB or CBRipoff. It adjusts them to account for your lag, and has to be used in combination with macros to take advantage of it. It essentially allows you to chain cast spells at the rate they were meant to be; instead of having latency add to your cast time.
An example macro:
edit: Added oCB and CBRipoff to the list
edit: Removed ag_UnitFrames from the list
is this essentially what Cirks FastCast was pre-TBC?
In principle, it's what Cirk's FastCast was trying to achieve.
In practise, the difference is that you need to create macros, and you can't just spam the button, since the addon can't block the stopcasting messages. But it does allow you to chain cast at the rate spells were intended to be cast at, regardless of latency.