I have to agree with the others on PGOs. I've got no use for them. That said, I do actually hunt with a pistol grip stock. It's not on a Maverick, but that's beside the point.
It looks like Choate makes a telescoping M4-style stock for the Maverick 88: http://www.riflestock.com/store/do/product/02-01-27
A gunfight is not the time to learn new skills.
If you ever have a real need for more than a couple of magazines, your problem is not a shortage of magazines. It's a shortage of people on your side of the argument. -- Art Eatman