Exhibit 10.79

                                                           [LOGO OF WELLS FARGO]

Real Estate Group
Orange County
2030 Main Street, Suite 800
Irvine, CA 92614
949 25l-4300

September 23, 2002



Mr. Preston Miller
ACF Investment Corp.,
801 Cherry Street, Suite 3900
Fort Worth, Texas, 76102

RE:   ACF Investment Corp., a Delaware corporation
      4000 Embarcadero, Arlington, TX 76014 ("Property")
      Wells Fargo Bank Texas, Loan No. #27840E

Dear Mr. Miller:

This Sixth Letter Modification Agreement dated September 23, 2002 ("Agreement")
is entered into by and between Wells Fargo Bank Texas, National Association
("Lender") and ACF Investment Corp., a Delaware corporation ("Borrower").

Pursuant to the terms of a construction loan agreement between Borrower and
Wells Fargo Bank, National Association ("Original Lender") dated June 29, 2001
("Loan Agreement"), Original Lender made a loan to Borrower in the principal
amount of Twenty Four Million Seven Hundred Eighty Thousand and 00/100ths
Dollars ($24,780,000.00) ("Loan"). Said Loan is secured by, among other things,
a Construction Deed of Trust with Absolute Assignment of Leases and Rents,
Security Agreement and Fixture Filing ("Deed of Trust") dated June 29, 2001,
executed by Borrower as "Grantor" for the benefit of Original Lender as
"Beneficiary" and recorded on July 30, 2001, as Instrument No. D201180713, in
the official records of Tarrant County, Texas encumbering real property
described more particularly therein; and evidenced by a Promissory Note dated
June 29, 2001 ("Note") and other documentation necessary to perfect the Loan and
any amendments or modifications thereto (individually and collectively, the
"Loan Documents"). Original Lender assigned its rights to Wells Fargo Bank
Texas, National Association ("Lender") by that certain Assignment of Promissory
Note and Deed of Trust dated September 24, 2001 and recorded September 26, 2001
as Instrument No. D201235560, in the official records of Tarrant County, Texas.

Said Loan was modified by that certain First Modification Agreement dated August
31, 2001 and recorded October 3, 2001 as Instrument No. D201241021 ("First
Modification Agreement"), Second Letter Modification dated November 7, 2001
("Second Letter Modification Agreement"), Third Letter Modification dated
February 8, 2002 ("Third Letter Modification Agreement"), Fourth Letter
Modification Agreement dated March 19, 2002 ("Fourth Letter Modification
Agreement"), and Fifth Letter Modification dated May 22, 2002 ("Fifth Letter
Modification Agreement").

Borrower has requested, and Lender has agreed to modify and amend certain terms
and provisions of the Note, Loan Agreement and Loan Documents.

MODIFICATION OF LOAN DOCUMENTS. The Loan Documents are hereby supplemented and
modified to incorporate the following, which shall supersede and prevail over
any conflicting provisions of the Loan Documents.

      Amendment to Maturity Date: The Maturity Date as recited in the Note, Loan
      Agreement and Loan Documents: is hereby modified from September 30, 2002
      to December 15, 2002.



      Amendment to Principal Repayment Schedule: Provided the Maturity Date of
      the Loan has been extended to the First Extended Maturity Date, commencing
      January 1, 2003, Borrower shall make monthly principal payments to Lender
      in the amount of Eighty Two Thousand Six Hundred and 00/100ths Dollars
      ($82,600.00) plus accrued interest. Principal payments shall be on the
      first day of each and every month. Principal payments are based on a
      straight line twenty-five (25) year monthly payment amortization schedule.

Lender's willingness to modify the Loan Documents is subject to the satisfaction
of the following conditions precedent:

      1.  Borrower shall deliver to Lender an unmodified, executed original of
          this Agreement;

      2.  The payment to Lender of a modification fee in the amount of $250.00;
          and

      3.  All payments due and owing to Lender under the Loan Documents have
          been paid current.


Except as amended herein, all other terms and conditions under each of the Loan
Documents shall remain unmodified and of full force and effect. Upon
satisfaction of the execution of this Agreement, the modification of the Loan
Documents shall be in effect.

IN WITNESS WHEREOF, Borrower and Lender have caused this Agreement to be duly
executed as of the date first above written.

            "LENDER"                                    "BORROWER"


WELLS FARGO BANK TEXAS,                        ACF INVESTMENT CORP.,
NATIONAL ASSOCIATION                           a Delaware corporation


By /s/ Stephen C. Melton                       By: /s/ Preston A. Miller
  -----------------------------------              -----------------------------
    Stephen C. Melton, Vice President               Preston A. Miller, EVP and
                                                    Treasurer