I will note that he claims to be including every attachment available for the BP, it is not just the right angle head. It does sound like he is including a lot of tooling as well as a like new Kurt vice which alone could run $450+.
If you assumed $2800 for the mill, $500 for the vise and $2500 in tooling with $1000 added for negotiating it might not be that overpriced. Of course that all depends on what tooling he actually has and the condition of everything.
$7000 will put you into most of the PM knee mills, but then you have to consider taxes, delivery fees, a vise ($600 for a new 6" Kurt), tooling (a lot more $$$$$), so this could actually be worth a look, as new could easily run you $10,000 delivered with a nice variety of tooling.
Edit
I'm not saying that this is a good deal, just that it could be, all depends on what it actually comes with. Based on the photos I'm not seeing the "every accessory made for a BP", I don't even see a rotary table included but if he has a lot more than is shown it could actually be a decent price.