K-30 fails-- many issues and questions. Help?

I will try to keep this short enough to actually read because I have several important questions and I'm really hoping for some help and advice.

Yesterday my K-30 fell to the dreaded Black Frame.  Before Christmas it was working well enough after starting each session with a short burst or two, but I guess a month of sitting, even with a full battery, was enough to do it in for good.  I took out the camera with the intention of lending it to friend who is considering the purchase of a DSLR, and no amount of bursting and or recharging was enough to get an image out of it.

I bought this camera, and the 18-55 kit zoom, from Hunt's in the summer of 2013.  I'm afraid I never filled in the warranty card, and by now it would be out of warranty anyway.  I suppose I could still get it repaired, but I have no idea what the cost would be, and frankly I am not sure if it would be worth the effort.  I can't imagine sending a camera in for any kind of serious repair would cost less than $200 and I think I might be better off investing that money in a better camera body.

So here come the questions.

1) What about the K-50?  Does anybody know for sure if a K-50 is subject to Black Frame? (I assume it is.) What percentage of K-30/K-50 models are subject to this failure, and at about what frame count does it usually appear? (I realize that evidence will be purely anecdotal.)  I can get the frame count off my K-30 body-- it was used quite heavily for the first year and a half or so, and then it started sharing time with my K-5iis.

I ask this for two reasons.  I like the small body size of these two cameras and am at least considering a K-50 body (bargain priced now) as an economical second body for myself.

More important, my friend (who is intrigued by my Pentaxes) is now considering purchasing a K-50 with the financial incentive of a semi-permanent loan of my two kit zooms. This will be her first non point and shoot camera.  She is not anticipating taking up the hobby seriously, but rather intends to record the life of her growing family with the two zooms and probably the 50mm f/1.8, which is also economical to buy.  Her shutter counts will probably be much lower per year than mine were.

Can I recommend this camera to her in good faith?  Does anyone have a high shutter count K-30/K-50 that is still working reliably?

2) Regardless of the answer to the above, I am now semi-seriously in the market for a second body for my Pentax lenses.  My choices are:

The K-50, the bargain choice and a very nice camera to handle, but which I am not inclined to trust long term without some serious reassurance.

The K-S2, with its tilt screen, is appealing in some ways.  Does anybody know if it is a close enough relative to the K-30/50 to be subject to the same issues?

The K-5iis, which is a known quantity and a very good camera indeed.  Learning curve would be pretty shallow at this point.  Good used versions are available at lowish prices and there may be some new in the box examples around as well if I want to hunt for one.

The K-3, which I understand is better in a variety of ways, but which has a much more demanding sensor. The learning curve would be much steeper. and this is the most expensive option.

I am not interested in moving to FF at this point as my lens kit, which is more or less complete, is based around the APS-C sensor.  Does anybody have any advice or opinions about my second body choice?

3) Sadly, if I do not choose to repair my K-30, I will have to trash it.  I realized I should keep the battery, charger, body cap and all accessories, but once I've done that is there any place to sell the carcass for parts?  Does anybody know a resource that buys non-working cameras?

4) Is there any reason to communicate with Ricoh to share my disappointment with the early demise of an otherwise excellent camera?  Is there an established complaint I can join? I don't really expect any manufacturer to cover the failure of a product long out of warranty, but a small credit toward the purchase of a new Pentax would be much appreciated.

Thanks ahead of time for reading and for any advice you can give me as I figure out where to go from here.