Oh, personally I do the -3 thing instead as well : )
Hmm, checking the Halfling Outrider, I guess it's the same thing. Oh well.
Although this is kinda interesting - Halfling Outriders stack with paladin, druid, and ranger levels. Druid 1 / Ranger 6 / H.Outrider 10 (CL 16, Mount level 11 + = 18). Hmm, not that great. If only I could sneak that paladin in there : )
Paladin 5 / Beastmaster 5 / HalflingOutrider 10 with Devoted Tracker? 15th level paladin mount (+8 HD, +10 NA, +4 strength, 9 int), 18th level Druid Animal Companion (+12 HD, +12 NA, +6 Str/Dex, 7 bonus tricks)...*shivvers*. That's pretty beefy.
Without equipment -
Riding Dog Mount (It is a halfling, after all : ) )
Medium Magical Beast
Hit Dice: 22d8 + 44 (143 hp)
Initiative +5
Speed: 50 feet (10 squares)
Armor Class: 41 (+5 Dex, +26 Natural Armor), touch 15, flat-footed 36
Base Attack/Grapple: +16/+26
Attack: Bite +26 (1d6+15)
Full Attack: Bite +26/+21 (1d6+15)
Space/Reach: 5 ft./ 5 ft.
Special Attacks: Trip (See wolf)
Special Qualtities: Low-light vision, scent, Emphatic link, improved evasion, share spells, share saving throws, Improved speed, Command, Spell resistance 20, Link, Devotion, Multiattack
Saves: Fort +15 Reflex +18 Will +7
Abilities: Str 30, Dex 21, Con 15, Int 9, Wis 12, Cha 6
Skills: Whatever
Feats: Pick 7 feats you qualify for : ), Alertness, Track(B)
And that's just your Mount; you're still a 20 BAB character pimped for mounted combat. Unfortunately, you only have 2 available feats (barring Strongheart Halfling or the like). Fortunately, your mount can beef up his combat presence with his 7 feats.
Oh, and you get a weak little animal too : )