Multiple DOS volume HDD emulator

So, I'm new to the forums here, and I've got a question.  First, some background: A couple months ago, I was straightening out a closet in my home office, and I came across a box containing some old Apple disks (mostly source code for programs I'd written).  I decided that just for laughs, I wanted to look at that old code so that I could gauge how far my programming skills have advanced since 1985.  To that end, I bought a Woz edition Apple IIgs on eBay, along with various peripherals (it came with a monitor, an Imagewriter II, a Unidisk 3.5, and a Unidisk 5.25, and I bought a few additional items).  I also bought an SD Disk ][ FDD/HDD emulator so that I could transfer my source code to my PC for posterity.  While working with the SD Disk ][, it occurred to me that it lacks one thing that I really liked from back in the time when lots and lots of people were using Apple II's, and that thing is the way that the Sider HDD emulated lots of DOS disks at once by creating lots of virtual DOS disks (including 50 track/32 sector ones), and allowing them to be differentiated using the disk volume number (presumably, just as Woz intended).  I was thinking about this, and it occurred to me that I could pretty easily make a card that could emulate up to 254 floppies, each with up to 50 tracks and 32 sectors, and have it work just like a Sider HDD did back in the 80's, which leads me to my question (actually, two, now that I've typed all this):

1: Is there already something out there (other than an old HDD) that does this, and if so, does anyone have a link?

2: If there isn't already something out there that does this, how much interest might there be in this thing at a cost of $125?