Not got any pics, yet, but just thought I'd post it in case anyone was thinking of doing the same. I had an old TNF Tadpole, which is a great tent, though light blue. I wanted to use it for wild camping. I'd been wary of dyeing it for fear of ruining the fly, but read a thread about someone who'd successfully dyed a nylon hubba hubba, so thought I'd give it a go.
Got a big jam pot and used idye poly, yellow and green at around 50 deg, and left it for a couple hours. I rinsed it until running clean then left it overnight to dry. I set the tent up this morning and turned the hose on it, and no leakage whatsover. It's a lovely slate green now, much better than the sky blue it was.
You can see the original colour at the bottom near the back. Actually, though, the fly was a bit lighter, and en mass, stood out a lot more than that thin sliver of blue suggests.
I'd add that from what research I did, nylon will work as above, though the colour you get depends on the colour you start with. For example, mine was blue, so to get it more green I added yellow along with green. For orange, I imagine if you added green you'd get a khaki type colour. You could try adding some blue as well to gt it closer to green, but you'd maybe have to expexperiment.
Here's a thread by some guy who dyed an orange Hubba Hubba. He used black which turned it a dark, reddy brown:
You have to remember to get the idye Poly, not the normal. And don't follow the instructions for simmering. I took mine to about 50 deg, but no higher. I did put the fly in at that heat, but then let it cool.
I also read that Rit dyes work as well. The guy in the link above uses Rit dye. As far as I understand, nylon is really good for dyeing, but it depends on whether it's coated, what the coating is, or whether it uses silicon fibers woven into the fabric for waterproofing. I think even with a coating, though, so long as you don't do anything to remove it, the dye works because it soaks in from the underside (I'm assuming the coating is transparent - though I could be wrong on that).
It's funny though how some colours work and some don't though..... I remember coming down the hill in Patterdale once and my mate got quite panicky that his tent had been stolen as we could see all the tents in the site bar his!! As we got closer we could make out his tent was there after all it just blended into the background so well. The really odd thing was that it was purple! - a quite livid purple (wild county I seem to remember) we could see all the green tents fine but it was the tent that looked so bright and gawdy up close was practically invisible from a distance.