A //c, //c+ hard drive query.... and hope?

[you@somehost.somedomain (Bart)]

I know I know. the HD20; The 20 meg hard drive designed for the early Macs that 
plug into the floppy port do not work with a //c or a //c+ due to some firmware 
considerations. But...
Was there not a drive that DID plug ionto this port that DID work on the //c?  
 I forget the name...

Anyway, if one drive could do it, then, how?  What was the dodge they used?  
Could it be repeated and re-created in the HD20?  My question is because I do 
have a few of these beasts and a few //Cs and I was thinking a marriage would 
be sweet.  

Is there a EPROM that could be updated? An adapater that could be built on the 
front end?  (-if this one then why limit it to the HD20?  You could then plug 
in ANY  ProDOS capable drive), or any dodge?. Limiting this to the HD20, is 
there ANY WAY you could modify the beasts to work in ][Land?

I am merely a network tinkerer, not a hardware guru.  Any ideas from the Big 
Guns out there?

-Bart 
Keeper of the Network from Heck