printing - How well do dye-sublimation printers perform with black & white pictures?

Most of the dye-sublimation cassettes have CMYO (= cyan, magenta, yellow, overlay) panels.
Are there any cassettes designed specifically for black & white pictures?
For example (and as jrista pointed out), some modern inkjet printers have additional black and gray inks to help to produce more accurate grayscale tonality — could there be like black, gray, light gray & overlay cassettes?

If not, how is the black & white performance with a regular CMYO cassette? Do some cassettes tend to tint the black & white picture towards to some colour?
Are there any example scans around the web, so I could judge by myself?

Or would I get better results with a modern inkjet (photo) printer? (I'd also like to see how they compare.)

I'm having a hard time finding up-to-date information via Google. wallyk's answer gave some clues, but as the comparison is from 2005, and (hopefully) both dye-sublimation and inkjet printing technologies have advanced, it could be taken as a rough estimate or merely as a starting point.

Answer

It seems that for e.g. Canon Selphy ES -line BWO (black, white, overcoating) cassettes are available. Also some fancy CMYO+Gold and CMYO+Silver options exist.

It should be noted that those cassettes aren't available for the Canon Selphy CP -line of dye-sub printers — but you've probably noticed that already, haven't you.

And what comes to your question about adding additional gray inks to achieve more accurate grayscale tonality: it is not necessary. Dye-sublimation prints are not dithered and every panel in the cassette is used only once for a print, so additional gray panels wouldn't add anything to the print other than cost. At least in theory, as midlevels could ease the calibration.

Sadly, I haven't found any scanned examples of B&W dye-sub prints via Google neither up-to-date comparisons to inkjet prints. Those would be interesting to see, though. Not to mention that it would be interesting to see how white is the white-dye. (I didn't find any detailed specifications on the BWO-cassette, so I can't be 100% sure are the grays achieved by altering black levels or mixing black dye with white dye. Selphy ES40's manual states the ink type as "BW".)