It seems that arrays can have 2 gigabytes of elements. This is according to what I read on the MSDN under the Language Enchancements for FoxPro 9:

Specifying Arrays with More Than 65K Elements

You can now specify arrays containing more than 65,000 elements, for example, when using the DIMENSION command. Normal arrays and member arrays have a new limit of 2GB. Arrays containing member objects retain a limit of 65,000 elements.

Note:
Array sizes can also be limited by available memory, which affects performance, especially for very large arrays. Make sure your computer has enough memory to accommodate the upper limits of your arrays.

The Library Construction Kit, which contains the files Pro_Ext.h, WinAPIMS.lib, and OcxAPI.lib, still has a limit of 65,000 elements. For more information about these files, see Accessing the Visual FoxPro API, How to: Add Visual FoxPro API Calls, and How to: Build and Debug Libraries and ActiveX Controls. The SAVE TO command does not support saving arrays larger than 65,000 elements.

For more information, see Visual FoxPro System Capacities and DIMENSION Command.