Second choice after FA31/1.8

Last summer I ruled out purchasing the FA31 due to its high price. Lately I have been reconsidering, but am amazed to learn that the price has risen in this short time by 1/3. Could this be due to rumours that a FF Pentax is forthcoming?

Anyway, I thought some of the forum members might suggest a similar focal length that might be a good alternative. Manual focus or slower apertures are not a problem for me. I have the M28mm 2.8, which makes a good standard lens. But I would like to explore that "something extra" that I often hear about with certain lenses.

Any recommendations?

Dan