I face the same situation. Coolscan LS-2000, SCSI interface, aging (Athlon2000) computer. After some research, I share my conclusions:
- No more USB-SCSI (or firewire-SCSI) converters available; did not see any used ones for sale
- If/when I upgrade my computer, it will be a modular box. Only way to support legacy interfaces. And, think: the all-in-one may look nice and tidy at first; less so with all the external attachments: extra disk(s), USB expansion hub, etc... Some compactness can be had with "slim" mini-towers and/or µATX motherboards.
- Plus, with the all-in-one your hands are tied wrt the choice of monitor. If your take the time to scan, you should worry about the quality of the monitor.
- Legacy SCSI cards will not have Win7/64 drivers, except some high-end Adaptec models (let alone the price, what would you do with ultra-wide low voltage differential connectors?). XP drivers are rumored to work under Win7/32. Fallback: XP/32 (not a bad system after all).
Good luck