It does sound a bit cult-like to decorate a candle with a living person. And it would hardly be a traditional candle.
Nadir's concerns are, I believe, the ones that ought to be foremost in your mind, Matto. This is an area where one ought to tread with the maximum of care.
Why not buy traditional candles and include with them a nicely printed prayer for either the archbishop or the bishop. (Don't Kinko and similar places do specialized printing on the sort of heavy stock used for invitations to weddings and other formal celebratory events and for funeral announcements?) For the archbishop, the prayer would be easy; something along the following lines:
"O heavenly Father, we beseech Thee, in the name of Thy beloved Son, to look favorably upon the virtues and good works of Marcel Lefebvre, Thy faithful servant and archbishop, and if it be for Thy glory and the sanctification of souls, mercifully hear our prayer that he soon may be raised to the altars of Thy holy Church."
A hundred or so years ago, when I was in high school, we students were regularly called upon to pray a similar prayer for the canonization of the founder of the Irish Christian Brothers, the Venerable Edmund Ignatius Rice. So far, no luck, but once Jorge canonizes Malcolm X and Martin Luther King, perhaps he'll find a moment to consider an actual Catholic. Or perhaps he won't—so much the better for Brother Rice.
It would be a bit trickier for +Pivarunas, but the wording might include something like "we pray that Thou wilt vouchsafe Thy servant the grace to persevere in his efforts to spread devotion to Thy holy Name and restore the holy Church established by Thy beloved Son to a state consonant with Thy will." And so forth.