In most of my (theoretical, experimental, and likely-never-to-be-released) mods, I've always made bodyguards like this:

- bump up the attack
- drop defence skill significantly
- bump up the shield value to 2 or 3 to compensate (marginally, should still be weaker in defence than the vanilla equivalent)
- regular cavalry size
- no upkeep + untrainable.
- tagged as the most defensive and reserved troop possible (Unit Class - column 18 in unit_prod)

the overall weaker melee defence reduces the Jedi general effect.
the bumped up shield and extra soldiers improves survivability vs cheap missile attacks.
the shield also doesn't add to the effect of heavy armour fatigue in desert, can be used for desert oriented factions (it's assumed that the general's BG has the best ventilated armour money could buy at the time :D).
the extra attack and reserved status makes for a unit used more as a last-ditch attempt for a decisive blow in battle by the AI (which is utterly heroic coming from the general).
the already mentioned perks of non-trainable + no upkeep.

Some of these effects are mostly assumed from rudimentary testing. I needn't remind you that a lot of my past modding was experimenting with the boundaries of the game and radically changing the units and their vanilla roles.
It would seem to work in theory, I've never tested how reserved and defensive the AI would use it and just how powerful its offensive capabilities should be, but that's the general way I've always wanted to make the bodyguards.

Just my 2 cents. :)