The highest I've found is 1600. Premier Equine sell these, but i'm sure lots of the others do too. You do have to be careful because some of the cheaper rug can be as low as 600...
I have a 2000 denier full neck made by gallop. Roo has not yet worn it but I'll find out shortly if it's as indestructable as it says!
Axiom (on ebay) do 1800D rugs at a very good price. They are pretty tough: my previous horse lived with a serial rug ripper (used to pull them backwards round the field by their rug) and it survived!
I brought a 1600 denier lightweight turnout from a company on ebay called hugrugs. It was cheap too and so far has lasted alot longer than any of the other lightweights I have brought. Last year I went through 3 of them before I got this one which is now on it's 2nd year of use. I'd definitely buy another. They are nice and deep and a good fit on my cob as well. My horse though isn't a serial rug ripper but a very playful lad who likes nothing better than a good game of nip chase with his buddies and it's stood up well to it all so far. I did however find it leaked very slightly at the top of the shoulders in the really heavy rain we had last week but only very slightly and not enough to make my horse wet.
If you find one please let me know! My serial rug destroyer (or his play mate) has been through countless rugs, it does not seem to matter if they are a high denier, or teflon coated, they have holes within weeks, some times days. I bought a 1600 (I think) denier Amigo rug for the summer, it lasted one night before there were holes! His Bucas 1800 denier teflon coated rug lasted a week! His expensive fly rug, bought because it looked like chain mail, lasted a week before there were holes. Nothing lasts! The rugs are ripped beyond repair on every occassion.
My guy rips his own rugs little sh**. He never used to which is the annoying thing? So like 1800D is generally the highest denier? Can anyone recommend a tough fly rug and fleeces also? What is teflon coated?
KTJ - Premier Equine Sweet itch rug all the way. Sounds like I am in the same situation as you. My homebred 4 year old take great delight in grabbing the front of any rug and pulling till it rips / comes off etc and then has managed to deposit bits of them all over his field. The PE one I bought earlier in the year has survived the summer (on 24 / 7)!!!
I cannot put any lightweight rugs on him so stick to middle and heavy weights now, all Mastas and weatherbeeta.
Good luck!!
Teflon coating is supposed to make the rug tougher. I think it does but it still not the complete answer. Bucas rugs are more expensive but not that bad. The one I have is a mid weight one and he is currently wearing this over his summer one with huge holes.