An 8th level Dread Necromancer (Heroes of Horror) has the "Undead Mastery" class feature.
All undead have +4 Str & +4 Dex & +2 hp / HD.
In addition, can control (4HD + Cha mod)/class level of undead via animate dead.
A Scepter of the Netherworld (Libris Mortis) allows a rebuker to rebuke (and one assumes, therefore command) as though three levels higher than normal. (mere 9,000 gp)
Rod of Undead Mastery (once again, LM) allows the user to control twice as many undead than he normally could. (10,000 gp)
The feat Undead Leadership (LM) doesn't feel like it should count against the number of undead controlled through other means.
Necromantic presence: Undead you control gain +4 turn resistance when within 60 feet of you.
Necromantic Might: Undead gain +2 to attack rolls and saves when within 60 ft.
Improved Turning grants a further +1, but may or may not be perceived as worthwhile.
So altogether, a 8th level dread necromancer, cleric, or similar could have quite an army of low level undead, through controlling and creating undead, controlling undead as an 12th level Cleric (therefore affecting Cleric Level +4 HD / 2 via rebuke) = controls up to 8HD undead.
And I don't think the desecrate actually allows the caster to command excessive numbers of the undead; it may create them an unusually large number, but the cleric gains no extra ability to control the extra number created. I may be wrong, of course.