As I have progressed, the need has arisen for an assembler that can assemble 4510 instructions.
I have extended the Ophis 6502/6510/65c02 assembler to include support for the 4510. This is a nice assembler written in python that is quite powerful and flexible. The source code is at http://github.com/gardners/Ophis. I have issued a pull request to the upstream Ophis distribution so that it will hopefully get included in the main Ophis distribution in time.
Now that I have a 4510 assembler, I can start extending the Commodore 64 Emulator Test Suite to include tests for all the 4510 opcodes, and prune out the ones for undocumented 6510 opcodes.
Once that is in place, and the tests pass on the FPGA, I will know that I have a working 4510, which will remove a significant unknown when testing booting with C65 ROMs.