For those of you waiting (and there are a few) here is an update on my DSSI 
work:

I've finally got a really great development setup. This was the fortuitous 
addition of extra hardware to the mix.

Kernel configuration goes like this:
	shac*	at ibus
	sii	at ibus
	dssibus*	at sii?
	dssibus*	at shac?
	dd*	at dssibus?
	dt*	at dssibus?

Since you can have multiple shac's but only one SII as far as I can tell. 
 From what I have been able to garner you can run the SII chip as either a 
SCSI controller or a DSSI controller but not both. The sii options will 
only work if you've defined KA640 in your config file.

dssibuses have a pointer to the device struct of the bus controller. That 
controller has to export a function for sending datagrams and managing 
connections.

I've got hooks in for multi-processor support but have _no_ plans to 
implement them at this time. Perhaps the next soul who takes this up can 
follow that path.

Watch this space for test kernel images...

--Chuck