Based on that assumption (that I also made when the NYT realsead their 1033 foia data) when I made a drill down for the top line items (based on foia submitted prices) for each county and associated them with the companies for those products[0], that they added to their wiki[1]. It's seems that BAE comes out on top if you also assume that the cost of the equipment by some measure is proportional to the opex (which we already assume could be greater than the capex). Here are the top ten with more listed in [0]:

~ BAE SYSTEMS TACTICAL VEHICLE SYSTEMS : $106,955,000.00, items: [u'2355-01-555-0908', u'2355-01-590-1660']
~ NAVISTAR DEFENSE LLC : $60,563,580.00, items: [u'2355-01-553-4634', u'4210-01-568-7116', u'2355-01-602-3357']
~ U S ARMY TANK AUTOMOTIVE COMMAND : $45,291,296.05, items: [u'2320-01-107-7155', u'2320-01-488-6962', u'1940-01-526-0770', u'2320-01-371-9577', u'2320-01-346-9317', u'2320-01-447-3892', u'2320-01-128-9551', u'2355-01-123-1606', u'2350-01-068-4089', u'2320-01-230-0300', u'2320-01-107-7153', u'2320-01-455-9593', u'2320-01-146-7193', u'2320-01-206-4079', u'2320-01-047-8750', u'2320-01-107-7156', u'2320-01-047-8754', u'2330-01-091-9005', u'2320-01-380-8604', u'2320-00-077-1632', u'2320-01-100-7672', u'2320-01-146-7191', u'2320-01-389-7558', u'2320-01-523-1314', u'2320-01-146-7188', u'2320-01-523-1127', u'2320-00-077-1631', u'2350-01-068-4077', u'2310-01-146-7194', u'2320-01-371-9584', u'2320-01-371-9583', u'2320-01-456-1282', u'2320-01-272-5028', u'2320-01-492-8215', u'2320-01-097-0249', u'2320-01-380-8233', u'2320-01-380-8213', u'2320-01-128-9552', u'2320-01-412-0143', u'2320-01-230-0303', u'2350-01-069-6931', u'3810-01-205-2716', u'8145-01-413-8521', u'2320-01-206-4078', u'2350-01-338-3116', u'2320-01-499-0015', u'2320-01-542-8463', u'2330-01-155-0048', u'2420-01-205-8636', u'2310-01-111-2275', u'2320-01-447-6343', u'5180-01-361-6874', u'2320-01-372-3933', u'2320-01-146-7190', u'2320-01-354-3384', u'2355-00-168-2620', u'2320-01-146-7189', u'2320-01-354-4528', u'2320-01-380-8229', u'2350-01-096-9356', u'2320-01-097-0260', u'2320-01-447-3891', u'2310-01-111-2274', u'2320-01-099-6426', u'2320-01-418-7400']
~ BELL HELICOPTER TEXTRON INC. : $21,933,282.00, items: [u'1520-01-020-4216', u'1520-00-087-7637', u'1520-00-169-7137', u'1520-01-043-4949', u'1520-00-133-9286']
~ SHORT BROS /USA/ INC : $10,680,000.00, items: [u'1510-01-418-1848']
~ NAVAL AIR WARFARE CTR : $10,000,000.00, items: [u'5820-01-435-2596']
~ U S ARMY TANK AUTOMOTIVE COMMAND AMSTA-IM-MM U.S: $8,581,181.73, items: [u'2320-01-050-2084', u'2320-01-230-0305', u'2320-01-206-4088', u'2320-00-077-1617', u'2320-01-047-8756', u'2320-01-230-0304', u'2320-01-354-3385', u'2320-01-125-2640', u'2320-00-926-0873', u'2320-00-077-1616', u'2320-01-230-0308', u'2320-01-230-0307', u'2320-01-206-4087', u'2320-01-047-8769', u'2320-01-230-0302', u'2320-01-206-4077', u'2320-01-431-1163', u'3805-01-028-4389', u'4910-00-735-6056', u'2320-01-047-8753', u'2320-01-133-5368']
~ HONEYWELL INTERNATIONAL INC. : $8,574,024.50, items: [u'1270-01-384-1108']
~ HALTER MARINE INC. : $5,110,617.00, items: [u'1940-01-549-9765']
~ WARNER ROBINS AIR LOGISTICS CENTER : $4,764,652.00, items: [u'3805-00-234-9778', u'1005-01-073-2368', u'2320-01-563-7052', u'3825-01-096-5554', u'2320-01-044-7133', u'6115-01-349-1536']

[0] https://github.com/TheUpshot/Military-Surplus-Gear/issues/10

[1] https://github.com/TheUpshot/Military-Surplus-Gear/wiki