The idea behind this build is to have Varus's W to be a bigger factor in his damage. While Varus is the newest AD carry in League of Legends not all his abilities are based off AD. His W and his Ultimate both benefit from ability power. If you would like to read more about Varus, his background and everything that can be found on League of Legends.

Pros

• His CD's are much shorter thanks to Nashoor's Tooth.
• The damage from W will be more significant.
• His ultimate would do a little more damage.
• Still a strong AD carry.

Cons

• Low Health.
• If caught without summoners or ult he is done for.
• Positioning is everything
• Skill shots must be hit to do maximum damage.

The runes are simply what I had on for him. The choice is completely yours. With these I am able to be more durable in some situations. The flat AD Marks and Quint are simply there to help with last hitting and to make this Q and E stronger. This is all up to you, it is simply what Runes I have had success with.

The Masteries which I have are fairly common and again these are to be changed depending on your play style.

By staring with Boots and 3 health pots you are more mobile and you can get into position faster for your skill shots.
By building Wriggle's Lantern it gives him lifesteal and damage just to start out the game and it gives him the ability to stay in lane longer, the armor is not bad either.
The Nashoor's Tooth is the item which will inspire a lot of questions and comments. I like this item because it gives a good amount of attack speed/mana regeneration/ability power. The ability power is at about 65 and that much AP allows his W to increase by 1% which may not sound like a lot but it stacks up. His ultimate also benefits from the AP and with the CD reduction his abilities can be cast more often to trigger his W effect.
Bloodthirster add's much needed AD and lifesteal.
Phantom Dancer is really valuable in that it gives Varus much needed movement speed and attack speed.
The Last Whisper and the Infinity Edge are for later. Choose whichever is more needed but the sequence in which they are placed I think to be a good one. I would sell the Wriggle's Lantern once you can buy the final item , be it Last Whisper or Infinity's Edge.

By focusing on his Q early in the game you can harass and pick up those difficult kills behind turrets or the runners. By level 10 his W should be maxed second because its active(by his other abilities) is powerful and it is much like hitting a character with two abilities while you are simply hitting them with either your Q or E depending on which you cast. I choose to level the E last because aside from the slow increase there isn't much there to be that big of a benefit.

These are the standard summoner spells which I pick up. Others such as Ghost,Exhaust,Cleanse, Ignite are also acceptable. With Exhaust and Ignite the Masteries must be tweaked a bit to get the benefits from these spells.

Teleport could be valuable depending on the player.

There are some which I would not recommended on an AD carry such as Surge, Promote, Revive, Clarity, or Clairvoyance.

Like a lot of Varus players know his W is activated by his other abilities. Other builds offer a lot of damage from his Q and E while their CD's are quite high. With this build his CD's would be significantly reduced to allow the damage from his W to be more significant. The CD reduction on his ultimate is also quite nice.

This goes without saying but farming is really important on all AD carries.

This build may not be called a hybrid build because it only has one item which add's AP. While if more items that add AP may be used in a Varus build one is enough in my opinions because his ration for the W % and damage on his is quite low and it would require a lot of ability power to add more. And comments ,questions and feedback is welcome. Please try to use constructive criticism. And finally try the build before you judge it. It has worked well for me I am just trying to share my experience.