I have one, too...
I got mine about 3 or 4 years ago... time flies. It was NIB on eBay, and I paid maybe $100 bucks for it. Only thing is they don't come with the bag or dirt cup packed with the machine. So, I just bought a bag assembly at work for however much they were, less than $50.
I packed it back in it's box when I moved to North Carolina... and never took it out. I need to find it now and unpack it now that I'll have more room to play with it!
Mine is the black and orange C1800.
They really are wonderful machines, solidly built, serviceable, quiet, and they do the cleaning job quite well. Sadly, the manufacturing of the Conquest has gone to China, now that TTI has taken over. --you know, pay someone in China even LESS to make it, so they can make even MORE of a profit-- but I digress.
We sold a LOT of them when I was at Hoover, maybe one or two out of ever 50 or 100 would be sold with a bag setup. People loved that damn dirt cup! I though they were a mess to empty and maintain... but still better than something with filters, etc.. A lot of them were bought by restaurants, churches, cleaning services. Only thing we were sure to tell them was to bring it in for regular servicing. And they did.
I did have the chance to examine one of the China-built machines in person, and was impressed with how well they duplicated it. There were a lot of small differences that were barely noticeable, but one could definitely tell that it was a different machine, even though it was the same. Make sense?
Thanks for posting your find! Enjoy it!