What SDKs can be used for creating offline maps application for iPad/iPhone?

we are developing an offline city map application for iPad, using Cloudmade SDKs. I'm curious, is there are any other SDKs which could be used for offline applications ?

Can Mapbox be used offline?

Starting today, Mapbox maps can be used without a data connection. The Mapbox Android and iOS SDKs can now pre-cache maps to save bandwidth and data charges, optimize performance, and anticipate lack of network access.

Can you download from Mapbox?

Tile ceiling & limitsAn app can download multiple regions for offline use, but the total offline download is capped at a maximum tile count (or "ceiling") across all downloaded regions. The tile ceiling is 6,000 tiles.

The better solution for me is:

1.- Generate your own maps with TileMill from Mapbox and then export to MBTiles format.

2.- Get the mapbox-ios-example and use the MBTiles file you just generated.

Starting with April, 2014 there is also skobbler's /Telenav's SDK - it's got full offline capabilities (map rendering, routing & rerouting) and a map cutting tool if you want a map of a custom area (e.g. you provide the gpx enclosed polygon and you get back a map of that area)

See some examples in the demo apps and the how-to's