There is no size limit that I am away of - other than whatever your computer can handle.
And as far as history goes - it only really keeps track of features. There is no history like SolidWorks/Inventor/other parametric modelers.
It does keep track of features and what they belong to.
Windows 7 x64, Precision T3400, Intel C2Q @ 3 GHz
8 GB RAM, ATi Radeon HD 3870 |