Just took 'Spine of the Akragaka' on rank 25 -- it was one of the cheapest edges this lowbie char could get. I am assuming here that edges are sorted in order from most expensive to cheapest.
For the record, char is d-elf AP. Mastered spear/polearm, but other skills (slice, thrust, pierce) were between 88-91%. It's quite possible you would qualify even if less proficient in the skills.
Here's the full edge list. After I took 'Lucky' and Spine, I could only see two cheapest edges. But this is probably because 'Lucky' is very expensive. Is Lucky worth it, btw?
[PROTECTED civilized indoor] <100%hp 94%m 83%mv 7472tnl (32.20%) 5 AM> discuss 2.
You have discussed your exploits so recently. You'll need to go out and do more before it is worth doing again.
You can choose the following edges:
Strong Wrists : Your wrists could be harder than normal to break.
Nightcaster : You can become a Nightcaster, focusing your magic's strength in the darkness.
Ehren Soul : You can call forth your Ehren Soul and its love of honorable combat.
Remain Conscious : You can train yourself to sometimes remain conscious when others might be knocked out.
Deep Pockets : You can develop deep pockets, capable of carrying more things.
Combat Statistician : You can be a combat statistician and analyze battle more precisely.
Courageous : You can show courage surpassing most.
Apt Learner : You can become an apt learner, garnering more from your experiences.
Lucky : You can be lucky.
Mousy : You could explain to your guildmaster the reasons you are unmoved by epic song.
Humorless : You can explain to your guildmaster the reasons you are unmoved by comic song.
Stonehearted : You can tell your guildmaster about your disinterest in romance.
Cheerful : You can tell your guildmaster about your cheerful nature.
Mudslinger : You can apply your knowledge of striking faces to kicking dirt.
Shieldspinner : You can train to spin your shield out of the way of cleaving blows.
Sightbinder : You can be a Sightbinder, stealing the light from the eyes of men.
Leader : You can be a natural leader.
Footwork : You can learn to avoid kicks better.
Shadowed Soul : You can hone the subtle nature of your soul to evade a paladin's attempts to t</span><span class="l36">rack</span><span class="d39"> it.
Cave Fighter : You can focus your fighting style upon combat in the subterranean realm.
Slasher : You can focus upon taking greater advantage of foes shocked by your slashing.
Spine of the Akragaka: You can learn to fight with spear and polearm to greater effect.
Strong Back : You can develop a strong back, more able to bear heavy loads.
Battle Tested : You can learn to slumber more quickly after the excitement of combat.
Transportation Sensitivity: You can hone your senses to detect transportation magic tugging at you.
Shield Eyes : You can modify your fighting style to better shield your precious eyes from harm.
Last Breath : You can learn to swim short distances when your life is on the line.
Keys to Success : You can learn to carefully handle keys made of the metal that burns you.
As far as usability of Spine, can't comment on it yet. I am not too impressed, but didn't do too much testing comparing it to sword + shield for tanking.