9mm Commanders fairly scarce
Your research so far is underscoring the fact that Commander size 1911s in 9mm are fairly scarce. I would guess that about 90% of the new and used Commander size guns are .45 ACP, and the remainder are a mix of 10mm, .40 S&W, .38 Super and 9mm. As for the reason, I could only guess that most buyers want the .45 and that fact determines what the manufacturers produce.
I can understand your preference for the cheaper 9mm practice ammo. I just bought some practice ammo at Walmart last week, and .45 is running almost $15 for a box of 50, while 9mm is about half as much.
I think that in your situation I might follow the path of least resistance, which would be to look at other 9mm handgun designs instead of the 1911, and have a wide selection to choose from. The 9mm is very popular and you'd have your choice of many brands and types. In a barrel length of 3.5 to 4.0 inches and compact dimensions for CCW, I'd look at:
- Glock 19
- Sig P228
- Sig P239
- H&K P2000sk
- S&W M&P compact
- Kahr K9 or P9
Good luck.