Check out Morel USA`s WR-8 or Morel Israel`s HCW or Elate 8
On Ebay it could also be wise too search for Macrom 59.21, 59.22 or Macrom Integra W-224. (the W-224 are what i am using as midbass, IB in doors)
All of the above mentioned speakers work well IB, have shallow installation depth...