Generally, longer focal length gives more pronounced OOF transition and bokeh at same distance. But I see your point, wanting similar bokeh goodness but with wider angle of view. Is that correct?
I have similar interest. I started with Pentax A 50mm 1.4 and zoom with my feet. It's sufficient for my need, from half body portrait to full body with some background, all with thin DOF and pronounced bokeh.
But then I got tired of manual focusing, my skill didn't seem to improve as much as I want. So I got a 77mm Ltd. So far I'm satisfied with result, I PP my photos less and less after using it. But, for wider portrait, I found it a little too long, I need to step back a lot, which often not possible. And even with 50mm I sometimes felt I need something a little wider so I don't have to step back too far.
Reading the FA Limited lens club certainly didn't help and so I finally bought a 43mm Ltd :ugh: . IMHO, 43 is the widest focal length I can get, which still gives OOF transition and bokeh that I want, for portraits. I have Kiron 28mm F2 and while it can create nice smooth bokeh I need to focus on something real close to get this, and thus it's not suitable for wide-ish portraits with thin DOF. I'm sure 31mm has better bokeh than my Kiron but still it's 31mm so I think it's not good enough for this purpose. I don't have a 31mm so this is just guessing.
So, assuming I understand you correctly, I think you should buy 43mm Ltd
It certainly will complement your 77mm nicely.
But if I was wrong and your real interest is small subject and flowers, then it's a whole different matter. At close focus (and macro) distance the DOF is much smaller for same aperture setting, so you don't really need very fast lens to get smooth bokeh. What you need to consider is the minimum focus distance. Oh well, I'll let someone else to cope with this. Goodluck!