In The Grappler's Manual, it is stated that there is no feat available to enable a grappler to use Dexterity for grappling checks. It has been 14 months since then -- are there any dextrous grappling feats now?
No, there is not.
However, you don't need one. This edition is often decried as the "Ask Your DM™" edition, but in this case, the fact that there are variants for the DM to introduce works in your favor.
On page 175 of the Players Handbook is a variant rule called Skills with Different Abilities, which outlines that in some situations, the DM can call for (or could allow a player to use) a skill check that uses a different ability score than normal. Some of the examples given are Athletics based on a Constitution check (for long-distance, stamina-based swimming) and Intimidation based on a Strength check (for a scary musclebound barbarian being scary).
Grappling is also based on a skill check; Athletics. If your DM allows it, then you could build around this variant and use a different ability modifier for your grapple attempts. Personally, I'm a big fan of this in games, because grappling is simple enough mechanically to be fluffed as many things.
- Strength-based Grappling: Default fluff. Grabbing someone and holding them in place.
- Dexterity-based Grappling: Dextrously locking down someone's movements; perhaps you acrobatically take them to the ground with a (Dex-based) Shove followed by a Grapple. Perhaps it's not even strictly grabbing them—instead, you mark their position and move pefectly to keep them from going anywhere, since you're always in the way as you and your opponent move within your spaces.
- Constitution-based Grappling: You're tough. You grab hold and no matter what they do, you just shrug it off and don't let go. Maybe you sat on them.
- Intelligence-based Grappling: Through your analysis of the battlefield and the enemy's movements, you can position yourself in such a way that their attempts to escape are ineffectual. It's no longer quite grappling, but we can use the mechanics (they can't leave once they're "grabbed") to represent a different sort of battlefield control.
- Wisdom-based Grappling: Your keen perception allows you to hit pressure points that hinders their movement, or something. Alternatively, it works the same as the Int-based "grappling" listed above. Or your monk training and meditation has caused you to be more than a mere man, with your mental abilities directly enhancing your physical ones.
- Charisma-based Grappling: You manage to keep their attention through some sort of taunting or perhaps an anime-style force of presence (they can't move because you're so overpowering just by being there that their body doesn't function).
There are many other possible explanations for something like this. This is in a muddy area between RAW and houserules. The variant is a RAW option, but whether or not it exists in your game is up to your DM. WotC has not released a feat for it, though. I think that they are probably unlikely to, because their design philosophy for 5th Edition so far appears to be more about enabling a group to create whatever game fits them best based on the chassis they've produced and sold.