You will find the easiest pistol to convert are Colt 1911 based pistols. There are many good .22 conversion kits for 1911s out there.
On the wife thing, remember it is easier to ask forgiveness than permission.
There are two times I buy firearms. the best option is when the wife is buttering me up for something she wants. The other is when she is already mad about something. She is already upset so buying a gun won't make much difference.
I now have a safe full and I’m bringing another home on Tuesday. She took this really well so now I need to figure out what she is wanting. Oh well I'll enjoy the buttering up until she let me know.