what kind of action bar mod do you use, if its macaroon (trinity bars with a new name) you can set up a button layout/profile with macros inside the buttons themselves... save the profiles and give it a name such as dk tank profile .... then load up and redo your macros in the bars for your paladin... then save that profile. Then all you need to do depending on what character you've got going with you, all you need to do is load up your correct profile!

its a little bit of front leg work, but i've done this and it works like a charm... the cool part is you can even set it up and save buttons positions and skills positions, so if you wanna try a new spec on your deathknight, shamans, or pally, you can save the profile you had, make a new one and save it with your different spec, then BAM! when you respec you wont have to do much but load the right profile to help! ! :thumbsup:

Of course you could also change over to a focus based leader system, and this all becomes moot I've grown accustom to using both systems together here and there, i make a bar and make it hidden or auto hide at the top of my screen and i can hotkey the buttons to help me change leaders on the fly... works super for my needs