Welcome to the Forum!
Love the looks and size of the witness polymer carry. Are there any clones of this clone?
The Armscor/RIA MAPP1 MS is a very similar direct Clone of the Witness P-Carry, made under license from Tanfoglio with many Tanfoglio supplied raw parts.
Then there are also the Sarsilmaz Polymer Framed Tanfoglio Clones, both of which I happen to own and run.
EAA imported SAR B6P and K2P 9mm Pistols
The Sarsilmaz K2P in particular is more common than the above referenced Armscor/RIA MAPP1 and currently on sale at low prices from distribution houses like CDNN.
However, it should be noted that the Slide assembly differs considerably from a Witness P-Carry, both in styling and Mechanical Lockup.
Sarsilmaz/EAA SAR K2P 9mm Field Stripped
It should also be noted that the SAR K2P will be replaced by the SAR CM9 Gen 2, so if you want the current style Pistol, better get one now!
SAR CM9 Gen 2
As for your questions on .22 LR conversions, some here have gotten the .22 LR Witness Conversion kits to work with their Sarsilmaz Pistols, but I much prefer my Ruger MkII, when it comes to .22 LR consumption.