That is quite an interesting observation regarding Thomas and Jesus. I've read through the responses here and many offer interesting perspectives on the nature and understanding of the passage.

I tend to understand this within the nature and understanding of what Thomas may have actually referred to. This is consistent with what John reveals about the nature of who Christ is, and the nature of Christ with the Father. When Thomas said Lord and God (as pointed out in other comments), I believe he was referring to a more Jewish perspective. This is based on the fact that John records Christ as saying to the Pharisees "Before Abraham was I AM" and their response in renting their clothes and picking up stones for blasphemy. Reason - Christ took upon himself the name of "I AM". Most students of the scriptures agree that Christ is YHWH of the Old Testament. Thomas expression and response very well be the recognition that Jesus was not only his (Thomas and the disciples) Lord, that Christ was also his (Thomas's and the other Disciples) God - or Yahweh - Yeshua.