I put this same request up a while ago. Couldn’t get any bites. All that’s wrong with my eyepiece is a missing eyecup, but I can’t find one anywhere for the mcii. You might have to buy a whole spotter or buy one on eBay. I’m decided to buy a different spotter all together.
FWIW I've had good luck getting Fieldscope eyepieces from Japan via ebay. I didn't realize these zooms were that scarce. I use the later fixed eyepieces exclusively (including DS versions) and am pretty darned happy with them and their nice, wide FOVs. I might be able to help you find a fixed eyepiece...