My previous post came out much more negative than I intended...
Apologies...

I have bicycle pedals for footpegs...  ...
Pffftt!... I don't know why I like that...
Can't say it's smart or practical though... ...

Best luck on yer' mod... and give us some finished pics...

Please post lots of pics of the install.  The other installs like this that people always link to have broken picture links, so they're pretty worthless at this point.

Another picture

why fully enclosed? There is no need to keep water off the battery.
12 volts is not sensitive to water and the battery is fully sealed.
you can run a garden hose over the battery and cables with no effect

So I finally decided and took the plunge,  I got the Earth X ETX12A and found a coupon code for 10% off so reduced from $169 to $153.  Considering it has a great warranty and is as far as I'm concerned is the best overall battery with its built in BMS (battery management system)  so I  won't have to spend an extra $50 or so just to properly charge and balance the cells.   If anyone else is considering the Earth X  brand,  you can go to www.warpoffroad.com and use coupon code: AZOP10.  That may just apply to the battery or the whole website but I was just happy it worked so I jumped on it.   I figure in the long run this will be the best choice and most economical given not needing any special chargers or cell balancers,  etc...   So Monday I'm expecting the battery bracket I ordered on eBay to come in and hopefully before the end of the week I'll have my battery too so once I have both of those I'll head over to the metal shop I spoke with and this project will finally be all ready to complete.   Many pictures will be included.   On a side note I am considering mounting the rectifier on the front outside of the battery and maybe having a piece of metal I can attach in front of that to protect it,  yet still leaving it open on the sides for ventilation.   Thoughts?

Using a fake oil tank for the rectifier, solenoid, ignition box and other electrical connections. Battery is well protected behind motor with muffler on one side, belt and belt guard on the other side, and swing arm to the rear.

So this weekend I'll be making the mod.   I got myself the Earth X ETX12A battery which with its built in BMS allowing for normal charging and the protection of over charging or going under powered and bricking I am very pleased with this and I got it (normally $169 plus tax and shipping)  for ten percent off with free shipping and no tax so $153 and no need to purchase special chargers.   Only concern is it is the widest of the ones I was considering and so I'm going to have to be clever about making this box work while still allowing me to put padding in for the batteries protection.  

Anyways I'll be posting pictures soon,  I had a wiring question first.   As I'm extending where my battery is by about a foot in terms of the terminals,  I called Earth X and asked them what size wire I should use and it took awhile getting in touch with the tech people but the receptionist relayed that they said '10 gauge @150 Celsius.'   I know what the ten gauge means,  but not sure about the rest?   Also I am trying to determine what I should also move to the box,  be it inside out our.   I think I want to mount the rectifier to the front of the box,  but I was thinking before that,  I should move the computer module that is held behind the left cover there and I forget what it's called but following all the battery wires they lead to a cylindrical bit of metal that is mounted on the fender also.   In terms of looks in the center obviously I'm going for the look of 'Black Beauty'  posted above,  I even want or am considering the metal plate mounted to the battery box bottom which follows up the rear of the frame (and any blueprints of what that would look like would be great),  but eventually I plan on having a bench style seat so the rectifier and the other thing I don't know what's called would eventually have to be moved.   That mod will be a ways away so it's not a rush,  but if it's something I could do easily,  I might as well get it done all at the same time so everything fits right,  not one thing now then need to move those things and have to find somewhere to put them again.

So I've finished my project.  It took me 10 hours last night between rewiring, making my own main battery wire with auxiliary cable, and actually getting the box mounted.  It was a lot more tedious than I thought it'd be.  I ended up having to remove the gas tank and exhaust which I didn't plan on, but now that everything is done, my new box got scratched quite a bit.  I didn't take any pictures as I was focused on getting done quickly and had school that morning (didn't finish until 5am) but soon I will take it apart and reassemble  with a good bit of photos to show the steps.   Now though where my battery box used to mount is just bare, so I'm thinking of putting a steel plate over it like on black beauty, and am probably going to mount the rectifier where the old box used to be.   Overall it's not a tough mod to finish , regardless of having a battery box or not, but making the wiring look nice is a pain, had to lengthen lots of wire's.  Also thinking of making that bit of steel follow the frame up to the carb, so I can mount things and more easily hide things beneath the seat and when I change my seat by welding on some DOM tubing, I'll have a little compartment there , ironically, I'll probably put my battery there once I change my seat this way, so this mod I've done could be just temporary,  but for now I love having the free space I've created by relocating the battery box.  
Ok so once again, pics will be coming soon, but it looks great!