I had an online version available about 10 years ago when Herbert started to implement the webserver component. I experimented with the "small" memory version and the "big" (> 2GB) version, both on a 32 bit machine with 4 GB of memory at that time. It actually didn't cause too much CPU-load at that time if I used the big-memory version. The problem was more on the input side which was a handmade HTML+JavaScript version that broke with every update of IE/Netscape/FireFox.
I think that I could recreate that later this month on a generic Azure Server and keep it up for a month to see how much that would cost. I am guessing that as long as the tables stay in memory and I limit the number of requests-per-user this shouldn't really put a dent in my credits. This is exactly what cloud-computing should make possible nowadays right?