Emilie,
My understanding is that NARA has not yet finished the filming of all 
the border crossing records (@Mexican border). They started with the 
smaller points of entry, leaving El Paso, TX for last. I think they 
hope to have filming completed by the end of 2006.
Have you seen the following site (explains the NARA plan)?:
www.archives.gov/genealogy/immigration/border-mexico.html
NOTE: border crossing records were created/kept 1903-1950; the first 
format of the records were based on records for ship manifests (records 
for 1903-1910)- this proved inefficient for folks entering on foot, and 
the format was revised and revised again over the years. I hope this 
information helps a bit. I, too, am waiting to see those El Paso 
records; my father crossed the border (age 4 yrs) at El Paso in 1916.

Have a good day - take care.

Natalie in VA