Well, keeping with the theme of high speed and good defense, I thought of a spread that is somewhat unique, although I used round, divisible by 5 numbers.
BST: 550
150 HP / 65 ATK / 70 DEF / 65 SP. ATK / 70 SP. DEF / 130 SPD
Physical Sweepiness: 104 Rank 0: Average
Physical Tankiness: 140 Rank 3: Good
Special Sweepiness: 104 Rank 0: Average
Special Tankiness: 140 Rank 3: Good
Offensive/Defensive Balance: Moderate Bias to Defense
Physical/Special Balance: 0.0 No Bias
Overall Rating: 309 Very Good
Now, let me explain. My vision for this pokemon would have to be Celebi and Blissey-like support in a faster, more defensive oriented version of Vaporeon or Hariyama. It would make a great bulky lead for either an offensive or defensive team. With Encore, both Screens, and Instant recovery, this pokemon could help bring defend against many common threats, similar to Cresselia, without losing its personality and uniqueness. For me, there would be nothing better than to have a pokemon switch in on a DD Gyara/Tar/Mence, Taunt or Encore it before it can DD (twice for Gyara or Mence) then Counter a coming attack for a KO. Like Wob without the "cheapness" and more options.
The Hp, at 150, is not a new number, but it is a very high number that allows for 101 subs before investing in HP. Remember that Giratina shares this deadly number. Keeping that in mind, I had to keep his other stats quite low to avoid creating another Cresselia. At 70 Defense each, neither are high and it poses a challenge on how to Ev this Pokemon. With many possible Ev spreads, it would add to the unpredictability of this to-be Pokemon. Plus, this would be an ideal user of either Counter or Mirror Coat, two useful support moves.
The Speed, at 130 is another important number. First of all, I did not make it "broken" as 140 would. This only ties with Jolteon and Aerodactyl. Most importantly, it does not reach into the speed range with Scarf Hera and others, like a base 140 Speed pokemon would. With 416 Speed, I would have to say that this Pokemon would be broken. Not the case with 394 Speed.
One of my goals for this pokemon was to be able to switch into faster sweepers and Encore their stat-upping move. Namely Garchomp and Infernape. With a + Speed Nature and just 32 Ev's, this pokemon can outspeed all SD Chomps and hit them with an Encore before they know what happened. There is also room to invest enough Ev's to beat Azelf and Raikou to their Np/CM, respectively.
I had to make sure that his offenses were crap after giving him such good offenses. After all, we do already have offensively capable support pokemon: Breloom, Hariyama, Vaporeon, Celebi/Jirachi, and others. The key for this pokemon is that it cannot invest enough ev's to be threatening as a sweeper. That is the price that its utility comes at. Even if all the ev's are invested in attack and speed, he cannot be that threatening, as his defenses won't be high enough to withstand many SE attacks thrown at him.
Counter/Mirror Coat would be a given on this pokemon. Hopefully it wouldn't be as dangerous as it was on Wobbuffet.
I underlined where I discussed each part of the pokemons base stat (minus attacking stats) to make it easier to read.