So what do you use to keep your stuff dry? Saw the rear cargo box on sidebysidestuff but it seems a bit small. Anyone using anything different?

[2015 Z Force 800 53/Trail EPS]

SuperATV has a real nice box for the Zs. I just wend with this diamond plate box.

https://www.amazon.com/gp/product/B000MK5LVG/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

Still looks OK.

I was thinking something along the lines of this guy for some more room, however after calculating what you have vs. this the cubic ft of storage is just about the same. I tend to carry a lot of "crap", IE: rain suit, small air compressor, small bottle jack, tire plugs, tools, etc. I have a smaller toolbox now, but it doesn't fit everything so I need something bigger.

That should work,  I just use a plano sportsman box. It's a bit small, but I get most of the items you listed in mine too. I would swap the bottle jack for a scissor jack to cut weight and size.

After spending a lot of time searching the web I found some nice large cargo boxes built to fit but I'm not willing to spend $500-$600 on one so I ended up buying this tote. It's stronger than your average tote and has a rubber seal with metal and plastic clamps to hold the lid on. You can even put a padlock on it if you want. Best of all... it was only $40 on amazon. It fits nicely in the bed too leaving some room around it but still quite large (21.8 gallons). I'm going to take a can of spray on bedliner to the top of it to paint it black and I installed a couple of hinges to make it easier to open and close on the trail.

https://www.amazon.com/gp/product/B01B3DN9V4/ref=oh_aui_detailpage_o07_s00?ie=UTF8&psc=1

Check out the cover for the storage area. Search YouTube for "scap doors" and there is an installation video. I believe the company may have gone under, but what a great idea to cover that area!

Im pretty sure Rodin has a rear storage thing from what I saw him post on FB

That's awesome, I do love things that have the branding on them. Mixed feelings about it being a soft liner. 
On a personal note: I love your quote. Makes me laugh every time I see it! Lol

That CF Moto soft case is pretty awesome, really like that one. I got this off of Amazon with free shipping on the scratch and dent section for $87. Normally I think they're 115.

[2015 Z Force 800 53/Trail EPS]

Wow...that fits nice!

I like it. It looks tough and fits nice. If I would have seen that one I would have bought it instead. What I have is working well too.

$104 Free shipping on eBay.
Really nice fit. 

http://www.ebay.com/itm/Dee-Zee-DZ91717P-Specialty-Series-Poly-Triangle-Trailer-Storage-Box-L-36-Back/161431522184?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D2%26asc%3D41402%26meid%3D1bd5cdd7887d4f1cb7ca9cfd89c70ce0%26pid%3D100005%26rk%3D3%26rkt%3D6%26mehot%3Dpp%26sd%3D301082796383

Went with this one from ATV TEK.  I don't think they make them anymore.  It fits the bed nicely, and easy to get in.  They also sell a 24pk portable cooler that fits it perfectly (which I picked up).  Still plenty of room for the chainsaw, too.  It was a $100 plus shipping.  It came in with some minor damage, so the seller discounted $10. 

more pics

Very Nice, Great purchase!