Might this one work?
It will fit in the trigger but not sure if it will fit in the flash.

http://www.gadgetinfinity.com/product.php?productid=16964&cat=318&page=1

GPGPU (General-purpose computing on graphics processing units)
There was some discussion half a year ago that the GPU (graphics processor unit)/video card wasn't really important for use with photo editing programs.
Adobe however and probably also others have put some efforts in using the GPU to do some calculations.

Here is a test to show you the effect a GPU can have on performance and also the amount off cores and Hyper-Threading Threads (HTT)
link

Sadly only few things are currently able to be handled by the GPU but in CS5 it's already more than it was in CS4 and also plug-ins seems to be using it more now.
If this continue it might be come a norm hopefully.

The Cactus V4 use a 3.5 mm (1/8”) mono mini-phone, the same jacket you've with earphones.

Like said normally the Cactus V4 comes with a 3.5 mm male jacket to PC male jacket in the box, that one can be used i think.
Hopefully it's also in the secondhand set you're looking at.

Here is a full spec list http://www.gadgetinfinity.com/product.php?productid=17204

It's 300 volts actually

I'm not saying that all older lenses did that only that it was less important for film.
I think the thread on luminous landscapes use that to base some off his theory on it.

That cactus can handle 200 volt on the trigger, hopefully that's enough?

Here is the official site from Yungnuo, as you can read Pentax and Samsung link

It's probably the extra ability to use the trigger as camera remote that makes it a nikon or canon.
If that's the case go for the one that works with Canon 450D, 500D those have the same contacts as Pentax.

This one is the one you want.
link

Sony doesn't make PC's by my knowledge although they have all-in-one desktop but those are more a laptop.
Alienware has been taken over by Dell and they are now solely aimed for gamers (with very ugly cases), they used to have some workstations but not anymore.
You're pretty much stuck with HP i think

The best you can do is make your own pc, that way you can pick all the high quality hardware from known manufactures insuring a stable PC.
Unlike Mac the manufactures off the hardware make the drivers so a lot also depends on them.
It's pretty much Murphy prove to build one although you need to be a bit technical.

I think this can be true with the older lenses because it didn't so much matter if the light falls on the film under an angle because the sensitive cells where on top.

With digital the sensitive cells lay inside the sensor but current lenses are designed to let the light leave straight on to the sensor and not under an angle. So this problem shouldn't really exist anymore.
Also the rear illuminated sensor have the photocells closer near the surface.

The triggers are standard triggers that Canon, Nikon and Pentax use and they don't support any form of TTL, it's just the center contact to trigger the flash there isn't anymore on them. And in that aspect Canon, Nikon and Pentax flashes work the same.
You can use a Nikon or Canon flash on your Pentax camera if you want.
First time hearing about a second shutter trigger

They work really simple.
- put the batteries in them
- set the channel the same
- connect them to your flash and camera and that's it.
You might be able to set the camera to trailing/second curtain, that way it will flash on the end of the scene but i don't know if the camera works that way.

btw the Cactus V4 comes with the PC cable that you need, don't know about the Yongnuo

But your better half has his own K-x right???
Ah well you borrowed his also some times