I've done all their missions, and I've got plenty of caps, but I kinda want to be ruthless, because I've no more need for the VG's, save for killing them for profit. Just curious about roughly how much money we're talking!

Depends on your barter skill.

Hey, dont kill the Van Graffs. But if you do, there must be around 10k worth of caps there. Assuming you don't blow the Silver Rush up, when you lose all that quality merchandise.

So that's it, I've said it before, but my faction allegiance is declared today. Pistolero and Lt Andronicus are Enclave, Styles is NCR, Gabriel and Meghan are Legion, Col Martyr is Mr House. But I pledge my allegiance to small time energy weapons dealers, just as eager to shoot you as to sell to you. Good times

You can steal all of their merchandise without killing them. Just come inside with a silenced weapon, crouch, take out the guards, then loot everything while the Van Graff twins aren't looking. If they're looking, pick the thing up, carry it around the corner and steal it there.

You can take all the weapons without killing anybody and without sneaking. Just grab all the weapons on display and drag it over to the room. Close the door and pick them up. Dragging items around doesn't count as stealing unless you add those items to your inventory.

I ended up not killing them. I decided there were better ways to earn 10k. If I wanted their stuff I'd have killed them for it though. On this play through I was a fairly amoral guy, and if playing nice was gonna take too much time or effort I'd take the quick option. That would have been killing the VG's...