> SBRs (real pia to get for non-leo)
It's not that bad.
The easy way is to find an SBR you want to buy, file Form 4 for $200, wait for a few months, then take receipt of your NFA item.
Or if you want to do a conversion from an existing rifle, file Form 1 (also $200) and get short barrel. The disadvantage is that you've then created an NFA weapon, so you'd have to be more careful how you handle transfer and sale.
If you don't want an NFA SBR, well, AR-15s can be pistols. Pistols can be short. Pistols can't have buttstocks, but there are legal products that are not "intended" to be used as stocks. They happen to look just like a stock, but they're totally intended to be used as an arm brace. If you do use one as a buttstock, that's not how it was intended to be used, but it is legal to do so. This approach is so popular that ATF has issued letters saying it's not illegal.
Here's most of what you need to know: http://preparedgunowners.com/2017/04/27/atf-reverses-opinion...
It's not mentioned in the article, but pistols cannot have a forward grip, as that would make them "Any Other Weapon", which is NFA. If you have a forward grip but don't have the tax stamp, you'll go to prison. Keep in mind you can start down the AR-15 pistol route, then later get your Form 1 tax stamp to convert it into a rifle by attaching a stock.
This is all quite ridiculous, but that's the law.