I suggest at this point a storage disk with 64k+ capacity, but only for a single type of item like stone or netherrack.

I won't implement this to avoid adding too many storage parts, and besides, there are other mods that do this already (like storage drawers) where you can use an external storage on.

after some thinking i would say 16m storage maximum for 1 disk would be more than enough.
you are at 64k and then upwards 256k, 1m, 4m 16m.
all after the 64k is for 1 item only and needs three of the former class cells to craft.

Yes, I might do that...
256k, 1m, 4m, 16m are the logical progression, but I'm worried it'll break balance, even if it only can take 1 type of item.

Well, such things are already available, just as blocks. Just make it relatively difficult to craft, IMO. And maybe even let them be disabled in config if a pack maker wants to limit it.

i didn't see it breaking the balance of the game
back in 1.6.4 and ae1 i have a wall of 64k storage disk in drives to store all my stuff including massiv amounts of cobble and normal stone. so going upwards with the capacity is a normal thing and the costs are fairly balanced for it.
to give it numbers:
256k is 3 64k, 9 16k, 27 4k, 81 1k
1m is 9 64k
4m is 27 64k
16m is 81 64k, 243 16k, 729 4k, 2187 1k(~34 stacks)
and belive me that is not imbalanced in my eyes to go all the way from 1k to 16m

Good idea, what size were you thinking about?

thats a good question
one question coming up, how much max storage per disk is possible?
is it capped at max int value of 2,147B?

It's capped to the max int value yes but I'd never add a disk in that comes close to that amount :P

What I WOULD consider: 128K Deep Unit.. Maybe more.

I'm a storage pig. I'll take the biggest you'll give me.

me too, but if it gets developt you can only store 1 item type per disc as mentioned above.
btw when it comes to dyes like diffrent wool colors each colored wool counts as 1 item type
also 1 item is a damaged sword, only a sword with identical damaged value can be stored.

In 1.7.10 with AE2 we would just use a deep storage unit which would hold billions (2^31 aka 2.147Billion) and we would just put a storage bus on it and bam, instantly hold a ton of that one item. If we had DSU's then I don't think this would be an issue. Perhaps not as expensive considering how limiting and also that it takes up a precious disk slot. I would say anything over 1M is more than anyone would ever use of that single item and while a nice to have feature it isn't OP and therefore shouldn't be arduous to craft nor super expensive.

Just some perspective.