The pro models occasionally still have the OG MIDI interface, but consumer models almost always don't. Anything with a USB port MUST have a driver for whatever vintage OS you are using, so they are generally a bad buy for that, unless they have the regular MIDI interface. What you should do is scour thrift stores, auction sites, consignment, etc. for older consumer/pro keyboards that are of the early 2000's vintage that would have the USB and MIDI ports, so you can get GS/XG/GM2 hardware that you can connect to a vintage computer. Once you identify a unit that could be suitable, dig up the user manual and support information for it to see if it would work for your particular uses. As far as OS support goes, XP is the best supported vintage OS, cause that's the OS where people were using USB and MIDI interfaces, along with the MIDI software often used in Windows 98.