I completely missed that posted a link to the article..
I was an f-15 mechanic in a former life....
Two seated f15's of the B and D varieties are rare, and may be close to only existing only in air national guard squadrens. The E mod is by far most expensive, but always has 2 seats...
Although the "E" mod it just a good as the earlier models from a "air superiority" stand point... They are much more reapectiable as a light weight high speed bomber.