It would be much cheaper to buy an EAA Witness. They make conversion kits that just slip right on the frame.
I have Witnesses in .22 LR, 9x19, 9x21, 9x23, 9x25 Dillon, 357 Sig, .38 Super, .40 S&W, 10mm, .41 AE and .45 acp. If I so chose, all those calibers could be fired on one frame, but I have pistols in most of those calibers and sometimes switch the top ends around.
Hope this helps.
Fred