Agreed. Don't buy gen1 modules for cars. If you're putting them in a climate controlled basement for a solar storage project, they can be good.
You need gen2 modules. Now, you could buy 48 of those and do what you describe, and it would work properly. However, you'd want to test each one individually and verify that they have similar capacity. The BMS can balance the cells somewhat, but a significant cell imbalance it will not compensate for, and you will potentially get terrible range. Remember, your pack is only as good as its weakest cell, since they are in parallel. If you have 47 good cells and 1 bad one, you could end up with a car with 6 miles of range. Not exaggerating.
Also, companies selling packs individually typically are charging more than fully assembled packs, so this is an expensive way to go.
Personally, I'd look for a 24kWh pack that you can buy from a totaled Leaf from 2015/2016 (Note: Some 2016's have 30 kWh packs, you can't use those). If you get the whole pack, then you can still do a cell swap yourself, or you could potentially do a pack swap using a tool from evsenhanced. For this, you wouldn't even have to open up the pack. If you do this, get ALL the plastic battery cover panels from the wrecked leaf, as the panels differ between the gen1 and gen2 battery packs. Also, you will have to buy some mounting brackets from Nissan to adapt to the changed Gen2 case.
Also, multiple people have decoded the CAN messages and mounted a 40 kWh pack into a 2011/2012. There's a place in Canada offering this:
https://cleantechnica.com/2019/08/10/a- ... -of-range/
And someone else who has done it:
So you might, maybe, just want to sit on it for a few more months, and end up with a range upgrade at the same time.