A pretty thin hammer-fired .40 S&W compact was the short-lived S&W 3rd gen 4040PD. It used an expensive Airlite Scandium aluminum frame and part of their PD (Personal Defense) line. A single stack 7+1 traditional double action (DA/SA). Think of it as a 3913 with a Scandium aluminum frame (similar to the LS or NL style frame) into which they stuffed the .40 S&W. It came with a black finished
carbon steel slide, which, interestingly enough, like the later production TSW models, was machined to take the optional spring-loaded, decock-only assembly.
The model was discontinued in '05, which was when I got mine. I was told by someone at the factory that they decided to discontinue the 4040PD, even while continuing to make the similarly sized single stack 3913TSW & 908 9mm compacts, due to the increased cost of using the Scandium aluminum frame in the 4040PD. It made the compact too expensive to sell for a competitive price on the existing market at that time. The 3913TSW/908's used the standard aluminum frame, so were less costly to sell.
While being a bit brisker in felt recoil than the 3913/908 guns and having 1 less round in the magazine, it became a relatively prized model among aficionados of the 3rd gen guns. The fact that it was only in production for '03-'05 makes it a bit harder to find used ones, though, and the magazines can cost upwards of $45 when found in-stock among some of the vendors.
The 4040PD uses the same nested set of (2) recoil springs as the 4013/4513TSW's & the 457/457S, and the same magazine spring as the 3913/908 series. The 4040's magazine uses a different follower than the single stack 9's, too.
It came standard with the Hogue rubber grip stocks (same as for the 3913/908 guns) to help mitigate the felt recoil of the .40 S&W in the thin, light compact.
https://www.genitron.com/Handgun/Smith-Wesson/Pistol/4040PD/40-SW/Variant-1