As a player and publisher, no I do not believe there is one.
There are a few PrC(s) that are out there already that are almost there. But publishing a PrC with just metamagic feats would probably consist of 5 levels. If it was 10 levels it would need something to synergize with it I think. But those are just my thoughts.
Everything Amora Games said +1. If I'd do one, just 5 levels and it better should have a unique capstone. Also, to my knowledge there currently is no class that would do this.
We did the Maven which has a lot of meta magic like abilities (Champions of Magic).
GM Elton, you still looking for a PRC with similar abilities?
I don't know of one that just awards metamagic feats, but I found a three level one that's pretty nice, the Metaphysical Spellshaper.
At first level you can take ability damage instead of raising the level of the spell, it grants a bonus metamagic feat at 2nd level, and at third level it lowers the level of metamagicked spells by one.
All you need is two metamagic feats and be able to cast third level spells. (and craft weaving 3, spellcraft 5, and knowledge arcana 5, but that's small potatoes)
It is 3.5, but if you are open to third party to start with that shouldn't be too big of a stumbling block.
The supplement is for sale on Amazon here, and online at Scribd, but I won't link it here.