?Does anyone know what all calibres the 220 came in. In particular, ?were there many 9's. ?ANY .38 Supers. ?40 S&W.

?Are any of these variant calibres, if available, compatible with a .45 frame. I ask all this because I am interested in a .38 Super or 9X23 - or a .357 Sig as a 220 SAS. I am presuming I could get an appropriate slide from Sig if I could find the right frame (assuming they exist).

Best I can tell, there were eight different calibers.

The German guns were stamped in:

45 Auto. (most all of 'em)
38 Super (common)
9mm Para (common)
7.65mm (somewhat rare)
9mm Luger (somewhat rare)
22lr (rare)
9mm Steyr (rare)
9x21 (factory converted from 9mm pistols in house, these are rare also)

The 9mm Luger and 9mm Para P220s can be considered the same caliber unless you have OCD like I do.
A lot of the .38 Super P220s were converted to 9mm before being sold in the US market using unserialized barrels.

The Sig US guns were made in:

45 Auto (common)
10mm (common)
22lr (somewhat rare)
9x21 (rare)

All of these can be used with the same frame with the exception of 10mm.
The SRT kit works in all of 'em.

I don't think they ever manufactured a P220 in 40 S&W or 357 Sig, but that caliber can be obtained through the use of a conversion barrel.

These are just the examples I have on hand. There may have been other variants available that someone else can vouch for.

I have a P220 in 9mm. It was a left-over from the Canadian RCMP with a stamp from a Seattle company. I was so impressed with my P220 in .45ACP, I asked the Sig Brain Trust and was steered to an on-line site that had some P220s in 9mm. I was not disappointed with the accuracy!!!