Ok, so I found the ghost wolf/flying/ground mount macro on the wiki and I modified it a bit more to what I was looking for and I thought I would share it in case anyone else might like it.
Here's what I changed:
It does everything the original one does. But when you're in a flying zone instead of only having the one option of a flying mount, you can hold shift and mount up on the ground. I found this to be helpful when I had a normal flying mount but had the epic ground mount. I find sometimes you don't need to fly and the epic ground mount is quicker. I also took out the "nostance" modifiers because I found they weren't doing anything really (seems like if you're in ghost wolf it shouldnt take you out of it w/ that but it still did for me) and needed the space. Depending on the length of the names on your mounts you could possibly leave those in there.

Anyways, here you go:

#showtooltip
/stopmacro [flying]
/cast [combat,nomounted][mod:ctrl] Ghost Wolf
/cast [nocombat,flyable,nomod] <Flying Mount>
/cast [nocombat,noflyable][flyable,mod:shift] <Ground Mount>
/dismount [mounted]
/cancelform [stance]