Could a commercial plane seat configuration look like a troop carrier?
Legally, you would need to find a seat that passed the FAA's 16 G "side facing" requirements. The AC that covers the 16G rule has some text that may be of interest on this matter. The FAA admits that its an ongoing area of research and that currently special tests need to be undertaken to certify one. (bolded for emphasis)  


  d. Side-facing Seats. 
  
  (1) General. All seats occupiable for takeoff and landing are subject
  to the specified dynamic test conditions. Included are side-facing
  seats and both single occupancy and multiple place seats, such as
  divans. Compliance with the structural requirements should be
  demonstrated for side-facing seats, using the same conditions for the
  test and pass/fail criteria as for fore- and aft-facing seats. The
  seat should be loaded in the most critical case structurally. Means of
  restraining the ATDs may need to be adapted to ensure adequate
  retention during the test. The application of floor distortion will
  need to be assessed on an individual basis, depending on the design of
  the fixation of the seat. The injury criteria of § 25.562 are not
  adequate to demonstrate equivalent safety of side-facing seats when
  compared to fore- and aft-facing seats. To demonstrate equivalent
  safety fully in the absence of such specified criteria, the applicant
  must use other injury criteria which may be derived from the
  automotive industry, which uses side-impact ATDs.  
  
  (2) Assessment
  criteria. Research into side-facing seats is ongoing. As research
  proceeds, the FAA will work toward establishing a more definitive
  policy with respect to the acceptance of side-facing seats. Until
  then, in the absence of specific compliance guidance, the FAA is
  prepared to assess side-facing seats on the following basis:  
  
  (a) The
  seat must demonstrate compliance with the structural requirement.  
  
  (b)
  If an acceptable side impact ATD has not been used with assessment of
  the corresponding injury criteria, it must be shown that the occupants
  are restrained in a manner that prevents substantial energy absorption
  by body to body contact (on a multiple occupancy seat) and which,
  using the best available engineering judgment, minimizes injury to the
  occupant(s).


The way this reads in short (at least to me) is that the FAA does not really test side facing seats all that often but they are willing to if an appropriate means of testing is devised, you can prove that people smashing into each other wont cause any serious problems and that your seats will be ok when a shock wave passes through the floor (same as the forward/aft facing seats). 

The FAA also has an extra supplement for potential injury from side seat configurations thats worth taking a read through "Supplemental Injury Risk Considerations for Aircraft Side-Facing Seat Certification"



On the evacuation note the FAA does not really care what the seat orientation is in terms of evacuation. If you are talking about converting a modern airframe you likely could not place a seat in front of the over wing exits but other than that so long as you comply with the evacuation time limits you will be good to go (from a strictly certification stand point). Since this configuration still has rows similar to that of a normal airliner I dont see why you would not be able to properly demonstrate evacuation capacity in this configuration. 



The biggest issue I see here is a lot of toes getting run over, and knees bashed by a galley carts...