I have a bunch of Hardinge 5DS collets, one complete and one partial 5C adapter for them. The 5DS system uses soft steel, machinable collets that can be cut as step or pot chucks and holders for whatever you can think of to fit within their dimensions. The system also has a built in, adjustable depth stop.
I have 41 of them, 13 step chuck and 28 collet, all have been cut in various ways but like with 'emergency' collets you can insert three 1/8" pins and cut them again for something larger.
I'd like to get $230 plus shipping for the lot. There's a guy in Minnesota selling smaller lots (19~20 collets and chucks) on eBay with one adapter or partial adapter for $249 and lots of the same number of collets and chucks without any adapter for $199. All used/cut.
Hardinge's price for a new 5DS step chuck is $80.50, for a 5DS collet is $60.50. New/replacement total would ring up to $2740.50, plus the adapters.
For the assembly with adapter and one collet is $199. Think of used ones as already having most of the cutting done for you, just chose one with a bore/depth less than what you need and save a bunch of time. :-)
All the parts are available from Hardinge so the partial 5C adapter can be made complete. The partial one needs the spring retainer, spring and the end nut that holds the spring. Could probably find a spring and nut to fit elsewhere and just buy a retainer, or if you're really into machining, turn and mill your own retainer and nut.