For independent client generation, we had good success with COMBs: http://www.informit.com/articles/printerfriendly.aspx?p=25862

The problem you mention with waiting on the database for SCOPE_IDENTITY() can be mitigated now (at least for one master child - not for a complex multi-level hierarchy or network) by using table-valued parameters for master/child data. All the data can be submitted cleanly to stored procs and easy use of SCOPE_IDENTITY() and OUTPUT INTO can avoid the round trips for that. This also mitigates any need for external transaction management around the operation from the client side since it becomes atomic from the client's perspective.