Hi Bill,
Yes, the LPC564xx has been on the radar for the future, but no development on it yet. If I remember correctly, you're using the original bootloader that used the HID USB driver, is that what you're looking for? I ask because the latest DZX code base has moved towards using the USB Device Firmware Update (DFU) class interface for the bootloaders. With Windows providing the WinUSB driver on Win7 on up, a custom device driver is not required, so it made more sense to meet the DFU spec rather than roll a custom one over HID.
If want to stick with the HID driver implementation and want development help with migrating your existing HID bootloader to the LPC546xx, we could explore doing some NRE contract work for you.
Regards,
-Tyler