Can I access an "extra" horizontal hortar using a gamepad on PC?

[Judge_Hellboy]

Short answer: No.
Long answer: Yes with scripting software you can best of both worlds but not without the fear of the banhammer.

Possible alternative:

IDK if this is what you're asking for but it may help.
As a PLD I have multiple defensive skills macro'd into one button.
L1+X (L2+X by default) hits a macro that has Sentinel > Awareness > Rampart on one button.
R1+UpArrow has Foresight > Bloodbath > Bulwark.
There is no delay in between the skills on the macro and since it takes at least a second to activate one it simply uses the first one of the 3 that is currently available.
On the right, above the battle log, i have a hotbar that shows the cool down of each individual skill so I can keep up with the cooldown status of my buffs that are hidden in the macros.

Skills like hallowed ground are on a second page to conserve room for the most used skills on the first page and so I don't accidentally use it. Its cooldown along with convert is off the right to see as well. If I want to use these skills independently I can always use ALT+# to use them. I usually keep the keyboard in my lap to type anyways.

This is also an old picture and my UI has evolved quite a bit and will continue to evolve as I the better I become but hopefully this helps somewhat.

If you are simply looking for more at your fingertip control there is some form of that coming in the near future.
Here is a link for you to read as I find it difficult to fully interpret what they're talking about.
http://forum.square-enix.com/ffxiv/t...=1#post1528335
It is a translation of a japanese developer post so it's rough but it does let us know improvements are coming. I am hoping we get a preview of it during the next live letter.