This is by no means definitive, but Anthony Rushing's great body of research (http://asms.k12.ar.us/armem/welch/AR_cav.htm) suggests the following:

Cabell’s Brigade (Brig. Gen. William L. Cabell)
1st Arkansas Cavalry Regiment (Col. James C. Monroe; previously Fagan’s) [assigned to Cabell Apr 63]
Hill’s Arkansas Cavalry Battalion (org Apr 63) [became 7th Arkansas Cavalry Regiment (Col. John F. Hill) 25 July 1863]
13th (16th) Arkansas Battalion (Maj. James Witherspoon) [served w/Cabell July-Nov 1863 then transferred to Marmaduke]

There were obviously others as these units would not have numbered a total 3,000 men