withit, I feel honored to have my name in your topic title!

I am glad you like my siggy too.
The context of that siggy was in some sort of humanistic psychology treatise, saying how the therapist should not be seen as an "expert" with excessive knowledge, but as an equal, collaborator, and guide in the journey that is psychotherapy, i.e. the therapist should not be idealized and placed on a pedestal. He is your companion/guide on your travels, and the knowledge and insights you bring to the journey are equally valuable and essential. But even though the therapist is not this sort of expert, he is indeed a master at developing the therapeutic relationship.
That quote just struck me early on in my therapy with my current T, who has told me not to place him on a pedestal, that he is just a regular guy, and he knows he is not the best therapist out there. (Ha, I beg to differ, but I've never voiced this to him. My dreams about him, which I've shared with him, are mutualistic so he knows what I really think and is well pleased, I think.) In retrospect, it was awe-inspiring to see the skill and speed with which he facilitated the formation of our therapeutic alliance. He has told me it is usually not that fast, that for us, it was "meteoric." I have always loved how he used that word to describe the speed with which we bonded. Even though I know he is an expert at developing therapeutic relationships with all his clients, it made me feel a tad special to hear him label our alliance that way.
withit, do you anticipate this plaque to be something your T would want to hang in his office for others to see? If so, I think just the including the quote, as you described in your post, would be good, rather than personalizing it with reference to your own experience. However, if you gave him a special card with this inscription, something that would be for his eyes alone (and maybe this is how you intend the plaque), then I think adding a personal allusion would be great, and meaningful. Anyway, that's JMO!