Dear-in-Christ Matthew and others,
I ran across something germane to this thread while looking for something else. Fr. Thomas Hopko says "Deacon and sub-deacons also wear a stole called the orarion, probably originally a piece of material upon which were inscribed the liturgical litanies and prayers (orare means to pray). The deacon still holds up the orarion in a position of prayer when he intones his parts of the divine services."http://www.oca.org/pages/orth_chri/Orthodox-Faith/Worship/Vestments.html
Sadly he does not provide any footnote.
In the reading I did earlier this week two things were mentioned as being written or potentially written on the oraria: 1) the angelic hymn "Holy, Holy, Holy" this is very much in sync with the symbolism of angel wings and this can still be seen on oraria today; 2) the donor's name.
As potentially strange as the latter may seem if anyone saw the exhibit at the Met earlier this year among the vestments and embroidered liturgical linens there were such things as donors' names embroidered. That is still common for many other things in church today except vestments AFAIK.
Since the above supports the original claim of petitions written on the orarion I think it is fair that it be mentioned.
One thing further can be mentioned. Slobodskoy says that the orarion is the same as the epitrachelion just in a slightly diferent form. All agree about this AFAIK. Slobodksoy says it represents the mercy of God flowing. I have only seen that symbolism attributed by him to the orarion. At the vesting of the priest when he puts on the epitrachelion the formula that accompanies it makes such a reference so ISTM that such a symbolism is useful and indeed may come from the formula/prayer or the formula/prayer from the symbolism. When the deacon vests the orarion there is no formula. When the deacon vests the sticharion and the cuffs the formula used is the same as for the priest's vesting.
FWIW I thought it deserved mentioning.