[rescue] hard drives for sparc10?

[Arthur Wouk]

the loss of one of my 10 year old hard drives (quantum fireball 2.1gig)
due to refusal find i think utmpx, has alerted me to a problem. these
10 year old or so hard drives are starting to die. i was still able to
scrounfe a functioning replacement, just a few years younger, and that
machine is now functioning. but other hard drives (three sparc10s)  are
showing various signs of old age.

i was able to find a younger mac/ibm DCAS04F and reformat it to work
on one of my sparc10s. it has 4.3gigs, and that is adequate for this
old machine. but what else is there available? (sformat allwed me to
convert it to 512 blocks.) (found it on ebay.)

1) are there other somewhat younger 50pin drives like the one i used 
which are reformattable to sun requirements?

2) are there any scsi-2 50pin hard drives which are substantially
newer?

3) is there a functioning 50pin to 68pin converter which would allow me
to use sca scsi drives at least in external boxes?  any experience with
these? i know there is no room internal to the sparc10s.