I found an E.M. Wallen (I could easily have misread Wallen for Waller when dealing with the handwriting) paroled from Company K of the Consolidated 19/20th regiment of Tennessee cavalry. The name appears to be from a list of prisoners surrendered at Citronelle, Alabama in May 1865 included in the microfilmed Compiled Service Records of 
Confederate Soldiers from Tennessee, microfilm series M268, rolls 69 and 70.

I made an effort to determine which soldiers were previously part of Russell's 20th regiment and which from other units.  I've found no records of an E.M. Wallen or Waller in the records and histories of Russell's 20th.  I thus suggest that EM Waller served with one of the other regiments that were combined with the 20th to form the consolidated regiment.  These include the 19th Cavalry, Ballentine's Mississippi Regiment (I believe the full designation was 2nd  Regiment Partisan Rangers), Faulkner's 12th Kentucky, and smaller organizations.

Company K, where Waller is listed, appears to have included men from Ballentine's and from Gen. Tyree Bell's "escort company" of which I've found only fragments of information.

Randel M. Price, July 2006

His wife:

WALLER, ELIZABETH DOYLE W/O E M
DATE OF DEATH: 02/22/1933
BURIED AT: SECTION CONF  SITE 71-A

 Photo Courtesy of Roxsanne Wells-Layton, June 2006