And yes, it was the Mirage G I was looking for. Let me throw some clarification on a few of these clues:
1) This plane was built by a well known manufacturer That being Dessault Aviation of France
2) This plane was designed to use tech that was new at the time. That being the "Swing Wing"
3) This plane featured a single engine and crew of 2
4) The tech used in this plane was also used on planes manufactured by allies and adversaries, some of which became legendary The "Legendary" aircraft included the F-111, F-14, Tornado, Mig-23, B-1 and Backfire bombers
5) Several of the planes referred to in clue 4 had service lives of over 20 years
6) Only one of the subject aircraft was built
7) The plane was cancelled due to two things the government couldn't overlook
8) The engine was not manufactured by the country building the plane The engine originally used was built by Pratt & Whitney
9) The single engine design did not give the performance or survivability desired.
10) While the plane was destroyed during it's third year of testing, the pilot was unhurt due to bailing out
11) The plane in question shared a fuselage with another aircraft that was also destroyed during testing
12) While the plane was completed in June, it was not flown until November due to changes, reworks and technical issues that had to be resolved
13) The time taken to go from first test flight to reaching it's top speed and performance capabilities was just over a month
14) From first flight to destruction of the aircraft was 38 months
15) The plane is question had a top speed comparable to many of its contemporaries of the day Even with the single P&W engine, it was capable of around mach 2+ according to my source
16) Since the plane was not produced, there was never any weaponry or hard points installed
17) The plane in question had a ceiling of almost 61,000 feet and a maximum range of almost 2400 miles
18) One of the "legendary" aircraft had side by side seating for the crew while the aircraft in question had tandem seating This clue, and the next two, referred to the F-111
19) The "legendary" aircraft was originally designed to have the same mission as the aircraft in question but, due to operational requirements and results of testing, it's mission profile was changed The F-111 was converted to a bomber
20) The "legendary" aircraft, other than the seating arrangement, actually looked very similar to the plane in question
21) The manufacturer of the aircraft in question has been around for close to 100 years Dessault opened it's doors, according to my source, in 1929
22) Unlike planes used in earlier wars, the plane in question used a feature developed by an ally that prevented compression issues in a dive This was the full moving horizontal stabilizer, pioneered on the F-86 Sabre
23) This plane's given name was used again on another aircraft that was not only successful but has seen combat operations The name Mirage was used on several fighters designed and built by Dessault
24) Like the "legendary" aircraft referred to in clue 18, the aircraft in question was designed to be used by both the Air Force and Navy of the developing country. Neither plane ended up meeting that goal Both the Mirage G and F-111 were slated to be land and carrier based fighters
25) The feature that tied all of the "legendary" aircraft to the aircraft in question was actually experimented with by an adversary earlier in the century. The "swing wing" was actually tried by a German firm late in WWII. How far that design got I don't know
26) The feature that was referred to in the previous clue was only able to be used on the ground when it was first tried. The "legendary" and subject aircraft were able to use the feature in flight
27) One of the "legendary" aircraft became famous for an operation that it was used to accomplish while another was made famous not just for what it did operationally but also by what the military did to "show it off" The plane that became famous for one operation was the F-111 bombing of Libya, the plane that was shown off was the F-14 due to it's participation in the movies "Top Gun", "Final Countdown" and TV show "Jag"
28) All of the other aircraft built(AFAIK anyway) with the the new tech, regardless of manufacturer, had at least two engines
29) Speaking of engines, one of the issues with the subject plane's engine was that it came from another continent, something that made shipping and receiving problematic in the event of hostilities.
30) Even though the subject aircraft was single engined, unlike the others from other manufacturers, it was supersonic capable like all of the other's with it's new tech
31) This new tech, used on the subject aircraft as well as the several "legendary" aircraft, was even planned to be used on the initial design for a Boeing built rival to the Concord that never got past the mock-up stage. That transport was later revised to a delta design with separate horizontal stabilizers
32) Some of the "legendary" aircraft were named after animals. Others were named after various types of weather.
Hope that clears up any questions on the clues