Since Primary Arms has those followers that convert mags to bolt hold open, I've been getting kind of spoiled. They don't work with the AK Pmags though, has anyone tried to convert the Pmags to hold the bolt on the last shot?

I have. I have done a lot of work to my mag. I can show you how to do this. If you like. I have also sent you a PM of how I converted my 30rd mag into a tanker 20rd. For those intrested, heres the link I posted on another forum....
http://www.firearmstalk.com/forums/f19/diy-magpul-ak-mag-project-20rd-113273/

I can show you what I did to mine in order to make the bolt lock on last round fired as well if you like.

Not sure I see the point. Sgammo has yugo BHO mags in excellent shape for like 12 bucks.

It's a curiosity thing

They've been out of stock for a while.

http://www.sgammo.com/product/surplus/5-pack-30-round-ak-47-mag-excellent-new-clean-hand-pick-yugoslavian-bho-magazines

They do have the good to excellent mags but from the pics seems like it's more good than excellent.

I can show you how to modify most steel AK mags into a BHO mag. Ceratin mags like the russians and romys can be done with only a pair of vise grips. Others like chinese with the rounded follower on the back have to be dremeled also.
All of my mags are BHO.

Sam does that to be upfront and honest about the mags condition, he's showing you the most flawed ones, in my experience you get maybe one like that out of a ten-pack. And in the description he is very clear about condition of the mags.He started doing that months ago due to a jerk who was complaining about the condition of one mag out of a pack, turns out he got a North Korean mag in a batch, and was re-selling it on GB for close to a hundred bucks and was wanting Sam to swap mags for him not because the mags were bad, but because he wanted to try and get another NK and didn't want to pay for it.

I don't see any other vendor of surplus mags putting anything close to that much effort into being upfront about the condition of the product. And if you are not satisfied with a particular mag, he will usually offer to buy it back from you, seen him do it many times.