Fixed base cutoff wheel tool?
It looks like you're in luck.  There's a good selection of tools called mini cut-off saws.  They take a blade or wheel of the size you're talking about.  Tiny saw blades and abrasive cutting wheels are readily available supply items.  Diamond wheels ought to be easy enough to find.  For example:

MicroLux® Mini Miter / Cut-Off Saw from Micro-Mark



The picture shows it cutting wood, but it also cuts metal (and other stuff) using the appropriate wheels.

A Harbor Freight knock-off: https://www.harborfreight.com/2-in-mini-bench-top-cut-off-saw-62136.html

Here's one of many at Amazon: https://www.amazon.com/TruePower-Speed-Cut-Off-2-Inch-colors/dp/B000VWHTUG.

Many offerings on eBay: https://www.ebay.com/bhp/mini-cut-off-saw