I converted the Aspis (Aspises?) a while ago - here's what I came up with:
Aspis Drone (Medium-size Aberration)
Hit Dice: 6d8+6 (33 hp)
Initiative: +3 (Dex)
Speed: 40 ft, climb 15 ft., jump 30 ft
AC: 19 (+4 natural, +2 shield, +3 Dex)
Attacks: 2 weapons +6 melee; or 2 slams +6 melee
Damage: By weapon, or 1d4+2
Face/Reach: 5 ft. by 5 ft./5 ft.
Special Attacks: None
Special Qualities: Aspis immunities, darkvision 60 ft.
Saves: Fort +3, Ref +5, Will +5
Abilities: Str 14, Dex 17, Con 13, Int 11, Wis 10, Cha 9
Skills: Listen +8, Climb +8, Spot +9, Move Silently +6, Hide +5, Balance +8
Feats: Multi-dexterity, Alertness
Climate/Terrain: Any temperate and underground
Organization: Solitary, gang (2-4) or nest (12-24 + 10-60 larvae and 1 cow)
Challenge Rating: 5
Treasure: Standard
Alignment: Always neutral
Advancement: 7-8 HD (Medium-size)
Aspis immunities (Ex): All aspis are immune to acid, cold, electricity, lightning, and stench attacks. In addition, they suffer only ½ damage from fire-based attacks (no damage on a successful save). In addition to standard immunities, larvae and cows are immune to visual or sonic-based attacks
IMO, if the PHB says that like bonuses don't stack, then a "racial" ability or feat shouldn't supercede that rule - no racial bonus or ability should break a game rule: so no stacked shield bonus... but I was going to rule that 2 shields act as a tower shield - no increased AC bonus, but it does provide cover.