So many questions, so little time.
I was imagining a 1500+fps round with about 40 grains of
weight.
That is simply not possible with a .22LR. You are in .22 WRM territory there.
1. Barnes Triple-Shock .223 bullets currently sell for about .50 cents apiece. Just for the bullets used for reloading.
Loaded .22LR ammo would easily double that price.
Would you be willing to pay $50.00 for a box of 50 .22 LR cartridges?
2. They wouldn't work anyway at attainable .22LR velocity.
Barnes Triple-Shock big game bullets work so well because they give very deep penetration in big game. (Something not needed, or desirable, for small game hunting.) At attainable .22LR velocity, they would act very much like a FMJ, and just shoot a .22 cal hole through the target.
3. Aguila SS-Sniper 60 grain loads are too long to stabilize in normal .22LR rifling twist.
I have tested them in Winchester, Browning & Ruger rifles, as well as Colt & S&W handguns, and in all cases, they gave terrible accuracy, and often key-hole & tumble at much beyond 25 yards.
4. The .22LR has gained it's reputation as a small game killer over the years more due to it's pin-point accuracy and ease of shooting it accurately, then by bullet performance. If you shoot a rabbit, or a squirrel in the head with one, it will kill it instantly. It matters not one bit if the bullet performs like a .300 Magnum Barnes performs on an elk shot through the shoulders.
5. Probably the best killing small game .22LR load today is the CCI Quick-Shok, or any hollow-Point load.
But the problem with them is, they aren't needed for head shots, and tear up too much meat with body shots.
6. My favorite small game load is any of the standard velocity Match loads. They give exceptional accuracy, and are quieter then Hi-Speed or Hyper-Velocity loads. Often, especially for squirrel hunting, the reduced noise will not scare away other squirrels, and make the likelihood of a full game bag much higher.