I don't know if it is a VFP limitation but you're asking for trouble anyway you slice it. Of course this all depends on WHY you need a form 4-3 screens high. For example: On 640x480 resolution the form height would be 2560 pixels, on 1600x1200, the form would be 4800 pixels.
Eric Kleeman - EDS Consulting Services
MCP Visual FoxPro
MCSD C#.NET
Hua Hin Thailand
Los Angeles California