[EE] Looking for serial high-side relay driver

Good day to all.

I'm retrofitting an existing product that uses lots of 12 dc or 24 Vdc
relays.  These relays all have one side of the coils grounded and take
incoming battery supply to activate.  We are adding a pair of cards that
allows the relays to be controlled over a 4-wire interface (Gnd, Vbatt,
data, data).  I have not yet decided whether to implement a simple SPI
interface or RS-485, based on what options the customer wants.

My old standby relay drivers (TPIC6595 or TPIC6C595) are not suitable
because they are low-side switching.  My question is: is there a modern
equivalent that does hi-side switching?

Another option is to float several 74HC595 shift registers from the
incoming battery supply line and use a whole whack of 2N4403 transistors /w
clamp diodes to drive the relay coils.  I would then probably use
opto-isolators to get the signals into the chips.  I will do this if that
is my only option.

Suggestions greatly appreciated!

Many thanks!

dwayne