Well... the PT145 should fit size. Many writers lament that the sub-compact 1911's tend to have problems feeding well... however the PT145 will digest most of what you want to feed it (however, I've noticed mine prefers the 185 gr over the 230... LSWC or JHP.
Cimarron has it right on the shorty .45ACP 1911s. Colt Officers model and the Para Ordnance are classic examples.
Both have had ammo or reliability problems in their long histories.Colt's usually need a trip to the gunsmith and stll may not work 100% reliably.Para introduced the Hog series, got nowhere with it for the most part, and then reissued the gun after warehousing most of them for a year or so.
Trying to get a compact 1911 gun to function well in.45ACP or other large caliber is a dicey prospect.
Engineering parts and springs strong enough to do the job and do it reliably are major hurdles to overcome.Mass and weight of particular parts has to be taken into account too. Downsizing things does not change the physics that have to be overcome. There is a law of diminishing returns at work here.
I am not saying that it can never be done, but there are lot of trade offs when going from a large pistol that has been engineered well to be reliable down to a much more compact version.
Since Taurus has reliable DAO pistols out there, why go through all the headaches to try and have a SA compact or subcompact that is going to be a headache in many ways?
DAO and DA tiggers usually have a little more whack to give a primer over SA triggers. There are exceptions.
I'd rather have the shipped grip with the longer slide. You still have the reliability and bullet velocity of the longer tube with the ease of concealment of the short grip. These have been made with a 4 -4.25 slide from the factory (Kimber and Sprinfield) and some customs have been done with a 5" slide as well.
At this point & time, I would just like to see a full size stainless model roll off the line. My dealer has had a open order for 3 SS 1911's for a year now. I'd like to get my SS so I can give my son my blue PT1911 that he keeps bugging me about.......any hope before xmas?????