It took some doing, but I've summarized my experience with upgrading to TF10 and put together a step-by-step guide. It ran a little overlong, because I like to use screenshots and it wouldn't all fit into a single blog post, but my hope is that this will address some of the questions I've seen come up in this thread about such things as configuring Tomcat, ODBC drivers, the TF XML client, RFC connections, etc. Some of it is SQL Server specific, but can probably be adapted to other platforms; some of it is platform-neutral.
It does not go into the details of configuring Payroll; that's outside my expertise. This guide is more from a Basis perspective in supporting Payroll and TaxFactory.
BSI TaxFactory 10 Installation/Upgrade for SQL Server
BSI TaxFactory 10 Installation for SQL Server - Part 2
BSI TaxFactory 10 Installation for SQL Server - Part 3
BSI TaxFactory 10 Installation for SQL Server - Part 4
--Matt