A used SP-101 might be found at that price. I would go DA if protection is part of the use. A ruger auto would be less and just as accurate.
I would also (and have) select/ed the Ruger MkII for this role you've described. Actually what I have is a MkII version of the M22/45. Goal is to replace upper with an aluminum Tactical Solutions upper and make it extremely lightweight, but with a 5in barrel!
Another solution worth looking into is the Ruger Charger pistol with a 10 or 12 inch barrel. Not as compact as a J-frame, but that is the handgun version of the 10/22, and perfectly legal. An 8in, 10in, or 12inch .22LR still gives 92+ percent of normal .22LR ballisitics and performance.
Yesterday at a gun show i saw several Ruger Mk1's for sale at @$250, some Mkll's available. One Mkll 22/45 was listed at $250, but i didn't have the jack (damm!).
A Single-Six is a solid piece and I'll pick one up after I have all my semi-auto .22's. (Or a Bearcat for really small hands!)