[quote user="ksurell"] I realize that there are interop calls to create cells the same way as in VBA[/quote]
When you install MicroStation CONNECT Update 4 SDK, you will find an additional help manual MSTNPlatformNet. That contains, for example...
CellElement CreateCellElement1( string Name, out Element[] Elements, ref Point3d Origin, bool IsPointCell )
It's in namespace Bentley.Interop.MicroStationDGN. It probably is calling the COM interface, but you don't have to: the InterOp is wrapped inside the interface that we see.