I don't know much, but those prices look nice enough to take a chance on and see. I found this on wiki:
http://en.wikipedia.org/wiki/Nonlinear_optics which
seems to say that xtal orientation is important for frequency doubling, but also says KDP is what's used to double YAG, not KTP as shown in the laser pointer diagram (which actually makes sense). The one laser pointer I took apart does look like #2 in your diagram. Their KDP xtal looks longer than what you'd use for frequency doubling, but ???
I have a really big ND:YAG laser that's deep purple rod, though you can get a red laser pointer beam through it. Looks like mine has either no mirrors or they were external. Huge krypton flash tubes (obviously this was meant for pulses). The guy I got it from (Frank Sanns) says it will punch though quarters when pulsed -- the caps and inductor are huge (1500 joules for 60j output).
I haven't had the guts to fire it up yet, not knowing what end any beam might come out of -- Frank said it works as is, however. I'd think it wants to be Q switched to get all the output into one pulse instead of a burst of them. There's some info here:
http://en.wikipedia.org/wiki/Nd:YAG_laser which interestingly says that the Nd:YVO4 might actually be a little ND laser in those laser pointers.
I know the YAG wavelength is one of the more dangerous to humans - a heck of a lot of "black" stuff is transparent to near-IR, which I've found out the hard way making reflective object detectors in that range, and it's close enough for your eye lens to image on the retina, so it's something to be really careful with at "power". If I were going to mess with it, I'd have some safety glasses (not that there's anything that will hold off watts -- but better than nothing) and some real good purpose-designed beam stops before I got in the room with that.
I once worked with a 10w green laser, argon, CW. That thing was a beast, a lot of fun (since I didn't own it and someone else fixed and fed it). Easy to make holes in things with.
Posting as just me, not as the forum owner. Everything I say is "in my opinion" and YMMV -- which should go for everyone without saying.