Tau Crisis suits are just too small.

[YorkNecromancer]

I've always been bothered by that. Like, how does the Tau fit inside? I mean, they have to fit into the chest unit, and in that, there's not enough room for her arms and legs.

But I've worked out what's going on. I mean, yeah, maybe the suits are Not To Scale or whatever, but I've been playing 'XCOM: Enemy Within' and so now this is absolutely canonical for my Tau army. (http://www.lounge.belloflostsouls.net/showthread.php?52693-Crisis-Suit-Rapid-Response-Team-conversions)

Crisis Suit users aren't like Marines. They're not just wearing the armour. They're MEC troopers. (http://xcom.wikia.com/wiki/MEC)

A Tau Crisis Suit pilot fits inside because they've undergone Basic Augmentation (http://xcom.wikia.com/wiki/Base_Augments) Their limbs have been removed completely, and so they wear prosthetic limbs when they're off the battlefield; we know Tau technology is good enough to produce some that are very advanced.

http://vignette3.wikia.nocookie.net/xcom/images/f/fe/XCOM_EW_MECTrooper.png/revision/latest?cb=20140121210735

However, when they're installed in their Crisis Suit, their base augments are removed, and they use the suit's own capabilities.

http://vignette4.wikia.nocookie.net/xcom/images/6/62/MEC_unlock.jpg/revision/latest?cb=20140120233008
http://vignette1.wikia.nocookie.net/xcom/images/c/c3/XCOM_EW_MECTrooper_Augmentation.png/revision/latest?cb=20140219200120
http://vignette2.wikia.nocookie.net/xcom/images/d/d2/XCOM_EW_MEC_Minigun%26KSM1.png/revision/latest/scale-to-width-down/603?cb=20140123235521

So any and all Tau Crisis Suit pilots have basically given up perfectly function limbs in the name of The Greater Good.

Frankly, if this isn't canon, it needs to be.

[Rev. Tiberius Jackhammer]

That's a pretty cool take on it, but I'd always assumed that they simply piloted from a fetal position - if you're controlling the suit and seeing through its cameras via wires plugged into your head, you don't really need a comfortable sitting position.

One factor to keep in mind is that once upon a time Battlesuit pilots could eject and run around independently (in the second Tau Codex, I think), but that point is easy enough to ignore in service of a headcanon.

[Jewelfox]

My understanding is that, not only are they curled up inside XV8s, they aren't piloting them using physical instrumentation. It's a direct neural link that allows them to "become" the battlesuit, which is part of why Tau mecha are so manoeuvrable.

Presumably you could do this at a distance, too, but I imagine not even the Tau have solved problems with latency. :p They wouldn't want people jamming their signals, either ... and they may also have noticed that they lose less hardware when pilots are physically embedded in the machines.

Don't ask me where I read that it's a direct neural link. >_> And the rest of it's just speculation. I like the MEC idea though! ( <3 XCOM)

[CoffeeGrunt]

The Fire Warrior novel says that Crisis Suits are controlled via direct neural interface. Apparently the mechanism is similar to dreaming, as it can sometimes disable the part of the Tau brain that paralyses the body during sleep. This results in some Tau sleepwalking themselves off buildings because they dreamt they were piloting a suit.

It's very feasible, therefore, that the Tau are semi-conscious and in a fetal position within the torso of the Crisis Suit, and control it without any physical interaction. This is how Farsight's Way of the Short Blade works, his suit has additional augmentations allowing him to 'feel' his suit to a greater degree, making him far more capable in close combat. We can probably liken traditional Crisis Suit controls to a one-way control like current prosthetics, where the user moves the machinery with interpreted neural impulses. Farsight's is like our next-generation prosthetics, that feedback touch, heat and other sensations to the user for greater control and integration.

Apparently damage/losing limbs for a Crisis Suit pilot feels like the real thing when their suit sustains damage in the field. However, they don't actually get sympathetic wounds like Titan pilots apparently do. They merely feel the pain.