Open Source OpenGL vector map rendering called MapBox GL, introduced here.  Quick  test run on iPad Air was successful and is available here :

Quotes from the site:

“Mapbox GL is based on the same vector tile format that powers Mapbox Streets. This means that you can use our global basemap, fully or in part, as well as create your own vector tiles to interleave data from different sources. Much like in TileMill, our open source map design studio, you can create a custom map by composing the various roads, parks, water areas, buildings, and more from lines, points, and polygons, then style them flexibly.”

“We built Mapbox GL in C++11 using OpenGL ES 2.0, a subset of OpenGL that is available on mobile devices and that can also run on desktop hardware with very minor changes. We use protocol buffers via pbf.hpp to implement a lazy vector tile parser, plus we’ve implemented custom code for text display and layout.

Mapbox GL is open source under a permissive BSD license, so you can check out all of the code right now. It currently runs on iOS, OS X, and Linux.”