I got mine at 59,75 in Feralas. If you stand at 58,76, you will be facing south. There is one directly in front of you and to the east and west of you that are not even 3 sec. walking distance. Took forever to find them but finally did. Good luck to all.

After you turn in the Hippogryph Egg, talk to the female midget standing next to the machine. She will have four quests available in which you have to bring her 4 eggs. You don't have to bring them in any particular order but the better egg you bring to her, the better prize you end up getting. Finding Hippogryph eggs and feeding them to the machine will just give you 250 rep points with TB and it IS repeatable. Only problem is that you can only carry 1 egg at a time and then you have to go back to Feralas and get another one.

The hippogryph egg's can be found at http://classicdb.ch/?object=141931

The Egg-O-Matic found at http://classicdb.ch/?object=142071 will give an egg crate for the hippogyph egg.

The Egg crate, when opened, give one of four different types of eggs.

An Extraordinary Egg - http://classicdb.ch/?quest=2747
A Fine Egg - http://classicdb.ch/?quest=2748
An Ordinary Egg - http://classicdb.ch/?quest=2749
A Bad Egg - http://classicdb.ch/?quest=2750

The Eggs are turned into Curgle Cranklehop. http://classicdb.ch/?npc=7763

(Quest #2747) if the link goes dead:

Elaborating on Glais' recommendations:

This is really in the Frayfeather Highlands. (makes sense since these are all Hippogryph-looking flying mobs)

What you might want to do is use the following location macro (modified from wowwiki.com):
/script px,py=GetPlayerMapPosition("player")
/script DEFAULT_CHAT_FRAME:AddMessage(format("[ %s ] %s , %s",GetZoneText(),(px*100),py*100)))

I use the "X marks the spot" icon (in the middle of row 23 of the icons)
I labeled this macro "Location"

Start just North of the small lake in the furthest SW corner of the map and move south then east along the hills.
Some nest locations to get you started:
55.9, 76
56.7, 76.6
56.3, 77.4
53, 71.5

At Level 49:
1050 xp when receiving the Egg Crate from the Egg-o-Matic each time.
1050 xp when receiving the Box of Rations after handing in the Egg Crate from an Ordinary Egg.
2100 xp when receiving the Box of Spells (Agility II and Stamina III) after handing in the Egg Crate from Fine Egg.

No reputation gain, but the quests are repeatable.(blue question mark).

I'd go with hearthstoning in Gadgetzan, but it's a toss up whether you ride from Thalanar or take another hippogryph and come south from Feathermoon.