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.

[EmSix]

Macro stuff

This is an awful thing to do because in later content your buff choices make the difference between life and death.

[Judge_Hellboy]

This is an awful thing to do because in later content your buff choices make the difference between life and death.

All my buffs and skills are accessible by using the current hotbar a keyboard bind or a second page.
There is currently no way to have all skills separately binded on the first page of XHB controls as there simply isn't enough room.
Proper and effective use of macro's increases controller use efficiency.
Just like proper and effective use of keyboard binds and macros increase keyboard/mouse efficiency.
All those buffs are also on another page so they can be used independently as well as many other skills. (Shield/sword oath, limit break, companion/stances, etc.)
The only thing I haven't solved yet is the use of Cover but I'm working on that. Very rarely is there an opportunity to use it so I don't get much testing.
I am normally an avid keyboard/mouse user on the PC but I dare say I am just as good with a controller in hand as a keyboard/mouse for this game.
But I will admit that it does take much more intial setup work and testing to properly prepare its use.