I hear you. I have a great BeltMan belt. VM-II and SuperTuck holsters for the Glocks. I know a guy my height who can hide a full size 1911 under an untucked t-shirt, but I can't.
I have no trouble making my 19 disappear carried at 3:00 under a sweater, or sweatshirt. But T-shirts and polo shirts it prints. So does the 26. I may be 70 years old but I have no 'gut' at all. None. A medim t-shirt hangs lose on me below the chest. Shoulders are just right, rest of it hangs loose but not loose enough to hide a gun as thick as a Glock. I wear pants with a 34" waist to include a SuperTuck in the waist band. The shirt is not quite loose enough with the holster to hide a Glock.
I can hide the LCP and P238 in IWB holsters, but end up pocket carrying them. A large t-shirt might work, but it's so big on me it looks like I have on someone else's shirt.
Between now and summer I'll be experimenting with the XDs to see if it's enough thinner to be IWB packable in the summer. I was able to pack the Shield under a couple of untucked polo shirts last summer. Alas, I sold it. Wish I hadn't.
I was looking at a SIG C3 Revolution yesterday. 'bout fell in love with it. If they outlaw greater than 10 round magazines I would rather have 8 rounds of .45 than 11 rounds of 9mm. Or at least that's the rationalization I'll use to buy one. : )
Fitch