Most of the functionality for this already exists. If you hover over the EQ plot in a regular channel strip, you'll see dots for the four main EQ bands.
Click and drag these to change freqency and gain. Hold down ALT while dragging to change Q.
Also, if the EQ hasn't yet been used in the project, and is in its initial off state, simply clicking and dragging one of the EQ bands will switch it on.
The only bits missing are an ability to toggle it on and off, and a way of using the high and low-pass filters.