potable desktop pack

That's a pretty neat idea. I think the main problem would be making sure the tower has sufficient ventilation, so maybe a frame it can slide into would be better than a back pack, something like a framed hiking pack. With a pad between your back and the computer so it doesn't burn you if anything overheats. You can also make it really small if you use the right tower; my own is a micro-ATX form factor, which is pretty small, but they come in even more portable sizes before getting down to laptop. I assume this is meant to carry the computer with you, then stop when it's time to use it, so peripherals (keyboard, mouse, etc) you should be able to just stow in a side pocket, or maybe even have their own fold-out frames (well, the keyboard and mouse pad, or maybe a trackball) like the monitor.

cool yeah thats kinda what I was thinkin like a droor or something that just slides out when needed

thanks for the comment

The primarily problem with creating a portable desktop set up is the power requirements are basically huge.  If you want to use the system for any significant period of time you either have to carry a large, and extremely heavy, array of batteries or a portable generator.  Neither are really practical and you'll have to be extremely strong to even consider it.

This then leads to the secondary problem of weight.  Since desktops aren't designed to be portable and that's not even counting all the other equipment you'll also have to carry with it.

The third problem is ergonomics and reliability.  Unlike 2.5" hard drives, 3.5" drivers by and large lack any shock protection that mobile use will require and a extremely heavy system would make portable use pretty much impractical to say the least.

So if you really want a portable desktop then you'll have to make some compromises to make it practical.  Like it'll be best if you switch to a low powered embedded system or at least a mini ATX set up.  An external power supply can help with size and heat issues to reduce the need for fans and you can more easily create a dedicated DC power system for it.  A SSD would be optimal but you can switch to shock protected 2.5" hard drives.  A discrete graphic solution may give you better video performance but it will also use a lot more power.  So it will be up to whether you want a gaming rig or not as to what you can cut but less would be better for portable usage.

Some mini ATX cases may be wide enough for a car style pop out motorized LCD panel, which will make it easier to carry with you by just having it retracted into the system when not being used.  These can also be touch screen and you can get a bluetooth or wireless USB keyboard/touchpad that you can easily carry with you to complete the basic set up needs.

Alternatively consider creating a cart set up, in which everything can just be rolled where you need it...  or a in vehicle setup where you can use the vehicle to do the heavy lifting and proving power.  If you have a hybrid car it would make the power set up much easier.  I recall one engineer used a hybrid car to power his house during a black out, whenever the battery got low the engine would auto start and recharge it and was pretty much self sufficient as long as there was fuel left in the tank.

@zeo:

For power, I was thinking that a regular power cord would be fine; like I said earlier, I had the impression that you tote this around with you, but stop to use it, and all sorts of places have easy plug access for laptop users nowadays. Also, there's no reason you can't use a 2.5" hard drive in a desktop computer (my primary drive is actually a 2.5"), or use a small shock absorption system for it. In fact, most SATA swap bays come with some sort of shock absorber, are dirt cheap, and there's no reason you can't use one for your primary HDD. I do like your idea of the bluetooth keyboard, though.

The touchscreen is also a nice idea, but it would require a little more engineering: You'd need to make sure the screen has a good enough frame to protect the edges of the touchscreen panel, and it introduces another set of wires (likely a ribbon) to connect to the main unit, both safely and probably along the screen's armature.

In that case then consider lan party gear...

Ex: http://www.thisnext.com/tag/desktop/items/?start=90

As long as the system isn't being moved about when being used, and is off when being moved, then you don't have to worry much about shock protection.  The touch screen unit I'm referring too is basically a pop out 7" screen and it's basically self contained and you just connect USB to enable the touch feature...

I have this one in my desktop for example...

It's a MozartTX case, but you can find at least one mini ATX case that will also fit it without modding (7" LCD).  There are 5" multi-bay panels you can use instead though.

My case is a bit of a monster, weight quite a bit with the aluminum casing but I have it on a dolley ( http://www.raisenroll.com/store_single.html ) to make it easy to move.

Alternatively, you can mod a LCD into the side panel... would be easier on the eyes and just have something to protect it while traveling.  Or you can use one of those USB LCD panels, perfectly fine unless you need to game... Any accessories can be slapped on with velcro and straps to make putting it all together and carrying it easier.