Beware of what you wish for, Jakeseacrest!
Yes, the KDS-85 offered for sale is going for nearly it's price when new and though it looks to be in great condition and would make a great addition to anyone's kitchen even today as a portable or a built-in, it is an obsolete machine for which just about every part has been discontinued. You CAN get the pump and motor assembly for it but not a timer if it should die(though I have a brand new one if anyone needs one!)
Various other parts which were carried over into the newer models may be available and racks are available on ebay for this machine as long as they come from an 18,19,20,21,22 series machine.
The one above looks to have the original style upper washarm which is the smaller arm you have heard referred to. The major difference between that one and the newer longer style is the addition of a water jet on the ends of the arm which helped to direct additional water into the corners of the upper rack.
I have that longer arm on my KDS18 so I cannot vouch for the results with the smaller arm, but I never have a problem with dirt or soil left in any of the glasses in the top rack at aoll and none in the glasses placed in the corners.
As far as your wish for a 19 or 20 series, Jake.. go for the 20. It is the same basically as the 19 but Hobart saw that the non heated dry system on the 19 was problematic in many circumstances. The 20 had the hot air blower returned to the machine and a separate no heat dry button put back on the control panel. Both machines WILL do a great job on the dishes but one should dry better than the other.
What you should really try to get is a 21 or 22 series machine since it has the really very well designed washing system with the metal food waste disposer in the pump that grinds up everything very fine and deposits it into the soil collection chamber for drain out later. The water is really filtered very well and the cycle times are long so the washing results are usually fantastic.
And Just for the record, the 18's were not that rare at all, They were well received and were very reliable(of course..made by Hobart)machines. The dual arms do a great job of cleaning especially with the 1/2 hp pump it came with.
Hope that helps.
Steve