A few gens ago I did 18/24 and had a blast. Used an heirloomed green crescent shield (58 width!) and 8 shield skill made it last forever. Beyond 6 shield skill your blocking speed and radius get crazy. I've caught arrows with a steel buckler that look like they landed on my elbow. I traded +3 1h weapons around as i leveled. Military cleaver, flanged mace, and iron mace were a lot of fun.
18 STR is enough to use any 1h, as well as letting you reach 6 power strike. I try not to go lower than that with 1h, since by default they are less damaging than 2h and polearms. 24 agility and 8 athletics lets you outrun anyone on foot, besides dedicated arbalest and the rare katana-having ninja. 8 shield skill lets you basically block with impunity no matter what shield you bring, loomed or not. You shouldn't need many points in WM if you're only using one weapon type so you can leave it low.
The only downside of this build is that you need to be at least level 32 to reach 18/24 with full skills. You can just barely fit it into your build if you skip ironflesh. Hurts most in strategus, where you will be much more frail than your fellow shield wall allies.
I've done 24/15 with heavy mail and a plate covered round shield as well. 8 PS will shock a lot of enemies at how much your swings hurt. 15 agi / 5 athletics was too slow for me though.
If you play DTV, builds with 10-13 shield skill are viable and will greatly increase your team's chance of winning. You pull the herd of enemies into a corner then just keep your nigh-invincible shield up while your team mows them down.