What should a pendant look like?

I've decided that my new router will have a pendant for ease of setting up work, etc. I have no experience of using one, but it seems like a good idea. My impression is that these often have push-buttons for operation. Reliable, robust, maybe, but it seems like a pretty clunky user interface. I would like single-handed operation, and avoid things like coarse/fine switching. I'm thinking that wheels/rollers, one for X and one for Y, with maybe weighted action and speed-sensitive response, could work well. Obviously, I'm thinking of building my own. I reckon I can sort out whatever electronics might be needed, and if I can't make something with a CNC router and 3D printer plus other machines available, I'm not really trying. Happy to consider an embedded micro-controller to add logic if it helps.

So, if you could design your own pendant, ignoring minor issues like whether it has to interface to Mach3, LinuxCNC, or whatever, what would it look like? Apart from basic x/y movement, what would it control? Wired/wireless? Looking for ideas here, and I'd think about how to build afterwards.

Most pendants don't want single handed operation because that makes it unsafe and very easy to crash by accidentally catching knobs buttons etc.

Step selection(course/fine) is critical with pendants and one of the single most used features. Blast across bed in Continous mode then switch to step and creep up on material. Having step resolution is important because you won't want to jog at full rapid when setting Z axis for instance but equally you won't want to jog in steps of 0.1mm while going down close to surface but when with in mm's of surface you will want to step into this 0.1mm or higher resolution.

For the electronics then I'd look into the POKEY's device if using mach3 as it gives loads of I/O which you'll need for a Pedant and it's designed with pendants in mind and makes it easy.
Arduino is the next thing I'd look at but again you'll need some way to let the control software know and lack of I/O with Parallel Port will be your enemy.!

So my minimum controls would be E-stop, Axis selection, Step selection, Step resolution, and axis jog buttons.
After this then things like spindle control or feed over ride, feed hold etc are things to consider.

What about including a control like this ?

http://www.3dconnexion.co.uk/product...ewireless.html

I don't care too much for this one but it's got to be said, a smartphone app, probably already exists ?

I started out with one of these: http://www.ebay.co.uk/itm/4-Axis-CNC...item3ce214d1eb

I had it before the machine was working and I thought it would suffice, it didnt.

I subsequently bought one of these, http://www.ebay.co.uk/itm/CNC-3-Axis...item19f0b5cf65

And while I know you're looking for design advice rather than purchase advice I posted this becuase without a doubt the most useful feature of the pendant I use now is the encoder wheel. It simply allows me great control of the machine from anywhere around the machine and allows me one thumb on the estop at the same time. I opted for the wired model becuase I didnt want to trust anything safety critical to wireless, my choice however and I'm not saying it should be that way for everyone, the long cable to be honest is a bit of a pain but I can live with it. Its not a total loss though, my four year old had the old pendant now and thinks its his phone :)

In terms of other benefits, having watched the machine rack itself just a little during construction I now watch the X axis screws like a hawk and find thats easier to do from in front of the machine which the pendant allows.