Caution: The following are only my personal thoughts. I guess for me the question would be, What is to be accomplished by such an act? Holy Communion, as I understand it, is an exceptional mystery, an expression not only of our union with Almighty God through Christ, but also of our participation in the Body of Christ (both that physical body and His body as the Church). It is for this reason, I suppose, that the Roman Catholics in their understanding have often referred to it as the "Most Blessed Sacrament." Although the outward form of consecration, using the ancient prayers, might be the same in all of the ecclesiastical communities you mentioned, and even more, if I do not consider myself a "member" of that community, why would I partake?
As many have said in posts on this forum, while we can say where God is (in His Holy Orthodox Church), we cannot say where God is not, and I dare say that I have seen many, many evidences of His grace in the lives of Christians who were non-Orthodox. No one can say that God could not impart his grace in a heterodox sacrament if He so chooses, but even so, we cannot ever presume to say with certainty when, where, and how this is done. To me, by communing there, that is essentially what we are saying, judging that, for ourselves, God has done something there. Nevertheless, having come to the fulness of the faith, why express, by receiving this blessed mystery in a definite, outward manner, my union, before God, with an ecclesiastical entity with which I am not in union? We are taught that, if we are not properly disposed, we should not receive it even in our own Orthodox Church; if we merely approach it with the attitude that we should "get it" or "receive it," rather than to think of the preciousness of the gift that is being offered, maybe we miss a lot of the blessing. I am reminded of St. Paul's admonition in 1 Corinthians 11 (with respect to the love feast) that we are not to look to the object, the ceremony, at the expense of its meaning. For me, as an Orthodox Christian, the meaning of Holy Communion is found in the Orthodox Church. Communing elsewhere just simply doesn't expresss this.
As for me, while I am content to fellowship and to share in the love of Christ with those in other communions, my respect for the integrity of the Church's wholeness precludes me from doing more, until such time, at least, when schisms are healed and we see the true fulfillment of Christ's prayer in John 17, "I pray also for those who will believe in me through their message, that all of them may be one, Father, just as you are in me and I am in you." Although I greatly respect, thank God for, and heartily admire the Christian testimony of those I know from other communions, many of my own relatives and forebears among them, I respect that we should not put the cart before the horse by sharing Holy Communion in such an instance.
Just my two cents.