I'd agree on function if nothing else- the Tempest has no weapons and just intends to be hard to find and harder to hit while running away.
i do have an eye for aircraft & navel vessels, military equipment etc. and i have to agree, i've often looked at the tempest and thought it had design similarities to the blackbird, they even share mission profiles, mainly stealth reconnaissance. and while the normandy shares many points of design functionality with the SR-71 i don't really think they match up visually. though i guess that's a bit more subjective, just like individual taste.
---edit
so on reflection, i still don't see the visual resemblance between the SR-71 and the normandy... however, i do see a lot of similarities between the normandy & tempest, so somewhere i guess the normandy likely shares similarities with the blackbird that i can't see.
