Yes, there are variations of this domain that exists or that can be registered but there is only one MetaCoinz.com.
#The Last and single Alternative
MetaCoin(.com) owned by Facebook Inc not for sale ,
MetaCoins(.com) Developed and not for sale,
MetaCoinz(.com) one and only short memorable alternative & the category killer (.com) in the area of Virtual coins ,Tokens,Block Chain, Gaming,Crypto related industry's
The English Alphabet last letter (Z) make this domain more memorable-Pronounceable and unique for branding,
Because of this fact using this for your online business can help you stand out and gain credibility and trust.
All reasonable offers consider!