I won't presume that anyone is interested, but since I started the question, I think it's only decent to post the result of my decision making process, since many of you read and/or replied to the question--so,
As the last post suggested, I finally went with the S&W M&P 15/22 and bought a Liberty Essence suppressor (....waiting, waiting, as the BATFE is Fast and Furiously processing my application paperwork. Funny how they waste NO time cashing my check!). It appears to be a quality built .22, is reputed to be very accurate and dependable, and the barrel is already threaded for the suppressor. Perhaps the best argument for it is that it has exactly the same functionality as "full sized" AR's, so training and transition will be superior to that of different platforms.
For those in the Upstate, I cannot say enough good things about Dexter at Freedom. He literally spent hours with me working on setting it up before I left the shop, fitting a Magpul AFG, the right scope mount, and other accessories so that the gun was 100% ready to go. For anyone who has not seen an M&P 15/22 or heard one fired suppressed, there is a nice video at Liberty Suppressors. Thanks again to all who took the time to respond.