I just purchased a Nikon S2 with a 5cm/1,4 that has 12 blades but I haven't had the chance to use it yet. I do have to add my thoughts on the Minolta Auto Rokkor 58/1,4. This lens gives the creamiest bokeh that I have ever seen from any lens. I have a few examples around here somewhere that I will try to post. But in the mean time check out the Rokkor files for comparisons of Minolta lenses and the bokeh they produce, you may be surprised.
Thy heart -- thy heart! -- I wake and sigh,
And sleep to dream till day
Of the truth that gold can never buy
Of the bawbles that it may.
The Zeiss-Opton Sonnar f1.5 on my Contax iiiA has 11 blades.. however at f2.8, f4, and f5.6 the circle is a jagged pattern. at other apertures, it is almost completely round.
Question: Wide open, arent most apertures completely round? It is certainly true for my Zuikos, where the aperture is completely out of the light path and a metal ring is all that is visible. Stopped down, you wont have much bokeh anyway.
Go not to the elves for counsel, for they will say both yes and no.
While not exactly what the OP asked, in my experience the number of blades doesn't necessarily correspond to good bokeh.
For example, my Zeiss (for Rollei) 35 & 85mm f/1.4 lenses have nearly triangular aperture openings (looks like 3 blades, but probably really 6 or more), but also stellar bokeh.
I can think of some RF lenses (presumably many-bladed - can't verify right now) whose bokeh I find pretty awful...