i guess the same thing goes for the macbook pro. they were all shipping with DVD drives…. then they decided they didn't want them on there any more and started making them with out it.
all the IIsi's that i have seen, all have the rom slot… and i'm kinda glad too!.
I have only seen (2) IIsi's that did not have ROM' soldered onboard.
One that i have here. and one other customer's. and i'v capped a whole mess of those too!
I have see a few of those with a 50.000 mhz oscillator on there!
IIx / IIfx / IIcx / IIci / IIsi/ SE/30 / Q700 -- all have rom slots.
and thank goodness for Dougg3's rom simm
as bbran said, the Mac II even has a spot for a Rom Simm… maybe someone could experiment with that

maybe i will ?
I am going to solder on a rom simm slot to my q800, load it up with 512megs of ram, pop in a 2mb simm with -ramcheck.
a good idea form bbran. -- i already got it running at 40mhz.