There is a solution, but probably requiring you to purchase some hardware....
I hit this problem when designing the BCR2000 control surface plugin. Consequently, the plugin supports 'fine control' mode where you can press the SHIFT key on the control surface and then turn any knob. This takes the MIDI CC coming in from the rotary control - which as you quite rightly state, has only 127 values - and increments/decrements the current value that the EQ wants to see by a much smaller amount, giving you fine control of EQ - certainly you can move around with 1Hz precision or so in fine control mode. (because internally Sonar controls all parameter values as floating point numbers from 0 to 1)
So - if you want to spring for a BCR2000, not terribly expensive - you can have all the fine-grained knobular control of EQ you like. The surface plugin is, of course, free to download, see other posts elsewhere in the forum.
In theory, the plugin would accept MIDI CCs from any source - it does not know or care what MIDI device is actually connected - and with an appropriately configured Novation it probably would allow you fine EQ control, thinking about it. You just have to send the CCs it's expecting, which are documented in the software release notes.