I think they do show the whole thing at one point at least, side by side with the D.
We see the Excalibur twice, and both instances are direct reuses of "Yesterday's Enterprise" footage. At the end of "Redemption pt I", the 23-ship fleet is shown departing - by pasting together footage of four ships, including a stern shot of the E-C. And in the middle of "Redemption pt II", the Excalibur is shown next to the E-D, and it's a shot of the E-D and E-C together reused.
So the Excalibur seems to represent the Mk I of that ship class, if Yamaguchi of DS9 "Emissary" and Zhukov of, uh, was it "Second Chances" fame are Mk II...
Timo Saloniemi