You can easily use two bucklers at the same time and be quite lethal - especially when the line between buckler and stabbing weapon (buckler+katar?) are quite blurry.
You can easily use a sword + buckler (NOT as a shield) - see Talhoffer:

Both fighters using bucklers here:

Google up bucklers - especially the more offensive ones.
Like the buckler that can be worn on the same arm as wielding a katar:


Or a fist-buckler:

Or a ... lantern-shield!
http://en.wikipedia.org/wiki/Lantern_shield

Anyway - I can agree that dance-like fighting while wearing two tower shields is pushing the line (but so is plenty other things in a fantasy world). I can agree that bucklers are more reasonable - quite deadly actually, when paired with katars (for example). Actually I'd even go back to the times when SU were wearing shields, if it was buckler+katar.
Too bad that actually finding the ideal solution for you lot would mean a hell lot of recoding (tower shields vs bucklers usage) ... or just go the easy way and remove shields all-together ... just leave bucklers for covering/shieldslamming. Could even rework current ones to change the looks and allow protection of an arm (1-armed bracers?) only.
Edit: could maybe work on attaching bucklers to 2-handed weapons?
Kender hoopak + buckler = hoopak with added AC? Less handy weapon-hits, but no decreased sling-hit.
Jet-black war-sword + buckler = finally some tanking usage (meaning ANY use for this sword)?
MBB + buckler = crappier shieldslam or cover (for lay AA mercs/glads) BUT finally MBB back into "usable" category again?
Such a solution could finally address the issue with 2-handed weapons being penalized for powerplay around Genesis (with only few exceptions - like gigantic sword, fbb, obsi halberd, etc.).
Imagine an Angmarim with a sledgehammer with an attached buckler, pulping things while still covering hits? Or the improvement for BDA (did I really write that now ...?) being able to use 2h swords without completely loosing cover+smack (just cut it's effectiveness by half compared to using a full shield)? Or the RDA+AA combo being usable (I didn't really write to improve Rage's killing speed now ... did I?).