There is a brand called Bit-3 that later became SBS (?)

I make some searches on eBay like
http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XSBS+chassis&_nkw=SBS+chassis&_sacat=0

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1313.TR0.TRC0.H0.XSBS+expansion&_nkw=SBS+expansion&_sacat=0

http://www.ebay.com/sch/i.html?_from=R40&_trksid=p2050601.m570.l1312.R1.TR10.TRC3.A0.H1.Xexpa&_nkw=Expansion+chassis&_sacat=58058

And from time to time they give results as :

http://www.ebay.com/itm/GE-FANUC-SBS-Technologies-85224042-Backplane-Controller-/200400234186?pt=US_Vintage_Computing_Parts_Accessories&hash=item2ea8c8e6ca

http://www.ebay.com/itm/GE-FANUC-SBS-Technologies-85224045-Backplane-Controller-/200510179276?pt=US_Vintage_Computing_Parts_Accessories&hash=item2eaf5687cc

But most of the time, I do not trust sellers that do not know what parts they are selling. But the truth is that the more ignorant the seller is, the cheaper you bought the part...

I looked for a manual for the SBS expansion chassis but couldn't find one. The SBS DD007-R (aka MH477) has the controller card built into the chassis itself so you don't need to install it into a spare slot on it. It apparently comes with an additional PCI card and a cable for connecting the chassis to your powermac but I can't find any info on which card and cable to use.

Let's see if we can get more info on these things...