I've got a character who is to dual wield tower shields. The challenges are attacking, as well as the feat cost. I've done most of the work on GitP.
In Plot and Poison: A Guidebook to Drow, there is a feat called Double Shielding, which allows you to employ two shields with an armor check penalty of -1 or better (so -1 or 0) and gain the armor bonuses and enchantment bonuses from both shields, while suffering the combined armor check penalty of both shields.
Shield Mastery from the same book explicitly allows you to bash with the mastered shield. Shield Specialization, from this book, not PH2, reduces the check penalty by a -1 (really quite bad for a feat…exceptionally bad really).
So far, if the feats required for this build (Shield Specialization and Shield Mastery, both from Plot and Poison) were to be removed, I would have a -2 ACP on each tower shield, and couldn't shield bash. The ACP being worse than -1 means I couldn't dual wield them.
The question here: How do I further reduce the ACP and bash with it while keeping the shield bonus to AC, without spending feats? So far I've not been able to find a way. Any published book is allowed.
(I don't care if "tower shields are bad." That's not the question.)
Best Answer
With 3rd-party sources available, one can reduce the tower shield's armor check penalty from −10 to at least −1...
But using exclusively Wizards of the Coast material to do this is, I think, impossible.
...But, sadly, nothing I've found permits making a shield bash with a tower shield
A tower shield (PH 123, 125) (30 gp; 45 lbs.) specifically can't be used to shield bash (PH 125). In fact, one can't even install on it shield spikes (PH 125). (True even in Third Edition, Plot and Poison being an unupdated Third Edition text.)
Green Ronin Publishing's Plot and Poison: A Guidebook to Drow, part of the publisher's Races of Renown line, lists as the entire benefit of the feat Shield Mastery as
Hence, one can't make a shield bash with a tower shield because of the feat Shield Mastery. Further, the benefit of the feat Shield Specialization is
Thus, even if the tower shield is picked for use with the feat Shield Mastery, the feat Shield Specialization doesn't enable a tower shield to be used to make shield bashes. The text doesn't allow doing so in the same nonstandard way that is allowed with the buckler.
The benefit of the feat Double Shielding says in part that
Most would read that benefit as Since one can't make a shield bash with a tower shield, the feat Double Shielding doesn't change that. Now, it's totally cool if the DM reads the benefit You can make a shield bash attack with your primary hand as also implying And the DM must concoct house rules for shield bashing with a tower shield, but that's not a reading I'd support. That's like taking a feat saying You can make an attack with a greatsword that does 6d10 damage or whatever and claiming that means a greatsword appears in the character's hand whenever he uses the feat and makes an attack.1
I spent some time searching through primary, secondary, and tertiary Dungeons and Dragons, 3rd Edition and 3.5 books, and making a shield bash with a tower shield seems impossible. Undoubtedly, there's some crazy publisher during the OGL boom that published a Tower Shield Bash feat or a slamming shield special ability or whatever, but I couldn't find a way to make a shield bash with a tower shield.
1 Okay, not really, but no analogy is perfect.