I don't believe that Tascam made a data recorder. This model appears to be the type of machine that was designed for security monitoring etc. (I could see this machine in a white van full of G men drinking coffee and eating,... well you get the idea).It's a discrete 4 channel machine. I see that you do archiving. What format are the tapes recorded in? 2 track mono was pretty popular for slow speed recordings and while this machine would probably do the job, I think you could find something that would be gentler on the tapes and fit the format better. Unless they're large reels, a Uher 4000 series goes all the way down to 15/16 ips. There are also slow speed models of Revox's.
If you're looking for an instrumentation recorder for playback of research data or something of that nature, that's a whole different animal. Something like a Racal Store or a B&K is what you might need. If so, the low speed on many of these was actually 1 1/2 ips.
Considering the fact that all of these machines will take a little elbow grease to get working properly, some are worth the trouble and others are not. They could probably all be had for very little money though.