I had a 186 series in stainless steel. I don't respect the 5.56mm NATO/.223rem as a fighting cartridge, but I do sorta kinda miss the gun. It's cute, handy, reliable and mine was fairly accurate. Not match accurate, but not too bad. Mine was never modified in any way, but if I still had one and were going to fix it up, I'd send it to
http://ruger-mini-14-firearms.com/index-2.html
for a .687 gas block, matching barrel(over 16" inches, please) and scout mount that allows use of open sights. I can "modifiy" my own handgaurd. There are a lot of other cool doo-dads, and honestly you don't need that scout mount, but I'd enjoy a setup like that as a toy or if I was someone who was satisfied with the performance of the cartridge, and it wouldn't cost much, especially if built on a used Mini 14. Oh yeah, have a synthetic stock for it.
You know, these things really aren't that bad. Yeah, it sucks about Ruger's politics and all, but you're fooling yourself if you think most of these big corporate types are any different. Look at what Colt and Smith did. Buying used means you get the gun but Ruger doesn't get the money. As mentioned earlier, an AK in .223 will do the same, though I like that cartridge even less through a 16" barrel. Heck, get a 7.62x39mm AK. Either way I'd take a Mini or AK in this caliber over an AR-15, unless part of the deal was I could sell the AR-15 for one of these guys. At least I trust a stainless steel Mini to work every time, and ironically, it's also lighter. You gotta love it when a solid steel firearm is lighter than a plastic and aluminum/plastic/steel hybrid. Kinda like the M-92 Vs CZ 75.
My ultimate advice is, unless you have lots of funding or an extensive collection already containing such a thing, forego the pea-shooter for a man's rifle in a serious caliber. An FAL, M1A, CETME/G3, SAIGA, VEPR will work just as good close in as they do far away. If overpenetration is your concern, get a SAIGA 12. Those things are impressive!