Linear FFT frequency response

I am trying to make a simple FFT based eq that will use a few sliders to control bell-shaped formulae, the resultant spectrum of which will be convolved with the FFT spectrum of the audio input. Obviously, the linear frequency response of the FFT is little use for giving good control over the spectrum. Does anyone know a way of skewing the FFT index so it will spread the frequencies logarimically over the bins, without leaving empty bins?

I had thought to skew the EQ spectrum using a mel scale, but this would leave a pretty poor low-end resolution.

Any advice is much appreciated.
Chris