smallest mounted ubercharger

[Baby Gary]

So I want to make a mounted ubercharger but make him interesting, so I thought 'Why not a really small one?' so I need some help finding a race and a mount that are viable from level 2+.

I don't need a ton of help with feats, I still wouldn't mind any cool combos that are not you bread and butter for a ubercharger.

[ExLibrisMortis]

Umm, a Fine sparrow hengeyokai wizard could ride their Diminuitive familiar. You can build a typical Power Attack/Arcane Strike/wraithstrike gish with Spirited Charge. Your attack range would be low by default, so you'd want blood wind as well (to use it alongside wraithstrike, persist wraithstrike).

[Inevitability]

Jermlaine rogue with a single level in barbarian to get Pounce and Wild Cohort to get a dire rat mount you can talk to?

EDIT: Tibbit soulborn is of course another nice option if you want relatively high strength but small size, though finding a saddle may be a bit harder.

[Gruftzwerg]

Kobold web enhancement (http://archive.wizards.com/default.asp?x=dnd/we/20060420a) gives em the "slight build" ability that let em count one size smaller if it's beneficial to them. This enables them to ride "small" mounts instead of "medium" sized. Or you could go DWK + wing feats to make a flying ubercharger.

Further they get claws which can be combined with unarmed strike (with beast strike feat). Together with a Necklace of Natural Attacks + Sizing, you can get a nice dmg boost (unarmed & claws at the same time = double profit) which is further boosted by charge multipliers (e.g. diving attack, "Sandals of the Tiger Leap", "Valorous" weapon enchantment).

And finally, they can be affected by dragon psychosis like "Ravening" (Dragon #313 iirc). This gives him +4Str -4Wis and the funny "eat or die" ability where you need to consume food in size of your own size category (slight build!) every day.