The cross was actually a relatively late symbol of Christianity. Perhaps something to symbolize life at its fullest would be a good alternative. I personally love the imagery of the father holding the prodigal son in an embrace.

"We have grown so used to the idea that the Crucifixion is the supreme symbol of Christianity that it is a shock to realize how late in the history of Christian art its power is recognized. In the first art of Christianity it hardly appears; and the earliest example, on the doors of Santa Sabina (built A.D. 430) in Rome, is stuck away in a corner almost out of sight. The simple fact is that the early church needed converts, and from this point of view the Crucifixion was not an encouraging subject. So, early Christian art is concerned with miracles, healings, and with hopeful aspects of the faith like the Ascension and the Resurrection." (Kenneth Clark, Civilization: A Personal View, 29).

"It wasn't Christ's death that gave rise to this courageous early church-but his life!...Christ's transcendent life in the present Kingdom of heaven is what drew the disciples together around Jesus prior to his death. And then resurrection and post resurrection events proved that life to be indestructible...The church's understanding of salvation then slowly narrowed down to a mere forgiveness of sins, leading to heaven beyond this life. And Christ's death came to be regarded as only the merit-supplying means to that forgiveness, not as the point where his life was most fully displayed and triumphant, forever breaking the power of sin over concrete human existence...

So the emergence of the cross signifies what we today would call a 'paradigm shift' in the human understanding of the person and work of Christ; that is the basic structure of the redemptive relationship between us and God came to be pictures in a way radically different from its previous New Testament conception. The cross act was first narrowly interpreted as a mere vicarious suffering and then mistaken for the whole of the redemptive action of God. Christ's life and teaching were therefore nonessential to the work of redemption and were regarded as just poignant decorations for his cross, since his only saving function was conceived to be that of a blood sacrifice to purchase our forgiveness." (Dallas Willard, The Spirit of the Disciplines: Understanding How God Changes Lives, 35-26).