Full armor for Omega tank100 cubic feet 4500 psi

Ebay should have something like "netting" that can go around the bottle to protect it from scratches and minor bumps. Search the SCUBA stuff. 
I don't know of much to make it stand upright. Generally, round bottom tanks are used laying down. I built a jig to hold mine a while back. Using 2x8 lumber, I made a basic "U" shape and cut the ends to cradle the bottle. Then, I used sticky back velcro on the bottle and the jig. The jig stuck to the bottle, the bottle wouldn't roll, it was high enough to make the valve easy to access, and I ended up with a little accessory shelf underneath! 
Sorry, I don't have any pics. The bottle does not fit in the center of the "U", it fits across the ends. If you hold your bottle in front of you horizontally with two hands, you'll see what I mean. 
Tom

Pyramid air has some also

The way Pyramid ships pellets is they have a square of foam with a hole in it that surrounds the circumference of the can . If you can get 2or 3blocks of dense foam 4 inches larger than the diameter of the tank cut circular hole in it and slide the tank in it. 
One other thing that would work is pick up a spray can of bed liner and spray the tank if it gets scratched just reapply. 

Take a look at Airgun Tailor. It is really well made and looks good, too.

Here is an easy but strong carrier made in the shop. It has a handle for carrying and will either stand up our lay down, My fill shop likes it because the can stand it on the base and it is out of the way. I used scrap to make it. One long piece runs the length. one square piece for the end (foot), two pieces of plywood with holes cut on band saw or sabersaw, and one long narrow top piece as a handle and to secure the mounts. I then put a piece of velcro to keep the tank from sliding out of the carrier. Works fine and adds about 1 lb. All parts are glued and screwed.  

AOA has a carry bag. I have 2

I use a golf bag cart with a metal bucket mounted where the bottom of a golf bag would sit. Foam lined the bucket and strapped the tank to the handle of the cart. Sits upright and won't turn over. Easy to use around the yard when shooting.

This is the boot I use for my 60 minute tank, just make sure you get the correct size https://www.leisurepro.com/p-fbrtb69/blue-steel-tank-boots-for-faber-tanks-67-69?gclid=CjwKCAjwj8bPBRBiEiwASlFLFcU6wyu7OJ-R4S5Z8cpFkcNLkMhJezN3Sk07nLnhhnoJuQBfPTKnTBoC9O8QAvD_BwE&kwid=productads-adid^88202999953-device^c-plaid^157352563033-sku^FBRTB69@ADL4LP-adType^PLA

Provides good protection and allows the tank to stand up straight on a flat surface, just be careful when you are outdoors because the tank can tip over. 

Add a tank mesh and one of these https://www.ebay.com/itm/SCBA-Cylinder-Valve-Protector-THREAD-SAVER-Scott-MSA-Survivair-Draeger-Avon/112490460765?var=412875709110&_trkparms=aid%3D222007%26algo%3DSIM.MBE%26ao%3D1%26asc%3D20160908110712%26meid%3D31afaf29ae704d62bd91621fee069914%26pid%3D100677%26rk%3D3%26rkt%3D3%26sd%3D112490460765&_trksid=p2385738.c100677.m4598 and depending on how rough you handle your tanks you should be covered against the regular bumps. Good luck.

take it to a scuba shop they have a boot for the bottom and should be cheep 5bux or so