I've managed to patch version 2.13 of Z26 to support 4A50 bank switching. I've sent the code to Eckhard for his approval; if he likes it, I should be able to release it. It auto-assumes that a 64K or 128K file is 4A50 format, and includes bank-switches in the log file. For example (left columns elided)

nvbdIZC 8c 11 00 f1  b8a6: 0c 44 6e nop  6e44	(*BANKS 22000/1E000/1C100*)
nvbdIZC 8c 11 00 f1  b8a9: 4c 89 b7 jmp  b789	
nvbdIZC 8c 11 00 f1  b789: 85 02	sta  WSYNC   
nvbdIZC 8c 11 00 f1  b78b: 85 02	sta  WSYNC   
nvbdIZC 8c 11 00 f1  b78d: 04 fb	nop  fb	  (*BANKS 22000/19800/1C100*)

The first number in the BANKS message is the base address for the range $1000-$17FF

The second number is the base address for the range $1800-$1DFF

The third number is the base address for the range $1E00-$1EFF

The range $1F00-$1FFF is always at base address $1FF00

Note that addresses $00000-$1FFFF are ROM; $20000-$27FFF are RAM.