BigMac,
I think you are in good shape here.
The Ricoh has the following advantages.
Copy mode is a 6-1 speed difference and higher copy quality on the Ricoh.
Scanning will be much better on the Ricoh. How do I know, because I have tested it against the HP.
One roll feed and only a 150' roll at that.
Do they really want to change paper that often?
What about different sizes?
The only advantage I see for HP is up to 42" wide size and color output/scanning.
Only if the customer has a requirement to scan in color do you have a problem here. You can still put a 30" roll on the Ricoh and print 30x42" drawings. Much faster as well.
Remember the ink yeilds on the cartidges for this machine are based on 5%. There is not a drawing out there I have seen which has a 5% coverage. They will be spending quite a bit on their supplies as well as having to keep more on hand since they will replace them more often.
I would look to see if set printing is an application here as well.
500' rolls make a difference for batch plotting.
Plus, you should be able to put a 240 in with an Encad plotter at about the same price as the HP.