I was checking out Henry AR-7s earlier and they gave me the idea/thought of hollow AR-15 stocks that goodies (mags, jerky, etc) could be stored in. Are there such things?

Most fixed stocks are hollowed out for cleaning kits, etc... They have a trap door on buttstock to access.

There are plenty of fixed stocks with storage compartments such as military type A1 and A2 fixed buttstocks.

The A1 type are about 5/8" shorter than the A2 type, the A1 was available a long time ago around late 1970s and the longer A2 stocks in the mid 1980s.

There are also modern commercial makers such as Magpul MOE rifle stock (MAG404) available in 4 different colors.

Other brands also makes the A1 type shorter buttstock which is Calvalry Manufacturing at an affordable price and there are many other manufacturers out there.

Fab Defense also makes a survival type collapsible buttstock GL MAG with built-in 10 round magazine quick detachable mag storage.

Magpul MOE Rifle Stock - direct link (click here)

Find a Cav 15 II stripper lower and you can have a nice goodie storage in your newly built rifle.

I have the MagPul MOE rifle stock on a few of my rifles, though I don't think I have anything stored in them.