crafting larger portable holes?

The real question: what's it cost to craft a portable hole full of beer?

I believe now wizards can cast demiplane to create a 30 ft X 30 ft X 30ft dimension. I'm curious if it's possible to combine that spell with wish to cast multiple demiplanes to stick together then use Wish to convert the created space into a portable hole with a single entrance? Once created find a way to cast fresh air spell I think its called and permanency on it. Im mixing 1e with 5e for spells. But if you have a large space with permanent fresh air you can hide indefinitely in it without leaving a trace behind. As long as you have food and water its a perfect hide out. Or a portable base to launch ambushes from. Plus imagine if you hide it on a gold coin then buy something from a rich business. the business shuts down for the night and you climb out of the portable hole inside the business vault to push all their treasure into the portable hole and then teleport away or wait to see guards scour the vault the next morning, and the portable hole now attached to the ceiling opens enough for a finger to pry it off the ceiling to fall onto a guard helmet to be carried out once the guard leaves(remember portable holes have no weight and a tiny part unfolded would flutter down weightless onto the guard.