I have some older Dahua 1.3 bullets. and a single 2mp dome-- 4 cams total. I was thinking about getting a few 3mp cams-- likely Dahua again. I could easily push up against that 8mp limit you came up with. What if I drop framerates to 10 or 15?
Heh...as for your links, the HP looks interesting, though still expensive I think. Now I feel like I could get a Dell Outlet desktop when they run coupon codes again. I got one a few months ago for the kids to use for homework-- under $400, with an i5-4460, 1tb drive, and 8Gb of ram.