I've been reading Frederick Christian Bauerschmidt's Holy Teaching - Introducing the Summa Theologiae of St. Thomas Aquinas (Grand Rapids: Brazos Press, 2005).
It's a great introductory read to the theology of Thomas Aquinas which has been an incredibly instrumental contribution to the Church universal. You have to take it slow to sink everything it as Bauerschmidt provides a selection of Aquinas' writings with commentary in the footnotes. As a result it is necessary to read some sections two or three times to take both the text of Aquinas and the commentary in. Whilst this is a time labouring task, it is essential nonetheless, given the differences in how language is used today compared to Aquinas' day.
One of the significant aspects of Aquinas' theology that continues to come out as I read is the understanding that "grace does not destroy nature but perfects it." I think this is a significant aspect of our understanding of grace. I think at times in our Western mindset we treat grace too much as some king of "thing" that we take into our possession through faith in Jesus Christ, rather than an activity of God himself. In using this thought of Aquinas it could be suggested that in receiving the grace of God our very being is perfected by that same grace. This is different understanding to the receiving of a "thing" concept of grace.
I see some correlations here to Wesley's understanding of holiness as "Christian Perfection", a term that he received alot of bad feedback about in his lifetime and since. However if we define "perfection" as the result of the activity of God's grace on our nature (rather than the focus upon the capacity to not sin as Wesley's opponents seem to focus upon), we come to a very positive use of this phrase. "Christian Perfection" then becomes the ongoing perfecting of our nature that is a work of the grace of God.
This is not reliant upon my ability to avoid sin, but rather on the boundless capacity of God's grace to continually cleanse and renew me. This is holiness. This is Christian Perfection.
In answer to my question in the title "is perfection possible?" - by the grace of God, it is.
"Be perfect, therefore, as your heavenly Father is perfect." (Matthew 5:48)