This must surely have occurred to someone already but just in case…
http://raspberrycolocation.com/ (Dutch company, terms and conditions are in Dutch which means we could do with some translation help)
Now I don't know what limits they would choose to impose on software but from the looks of it you can choose your own OS by sending them a Pi with an installed SD card rather than buying the Pi from them (in which case they do a default Raspbian setup). So if someone were to assemble a suitable OS, vm, Seaside setup and package it as an IMG/IMZ file suitable for dumping onto an SD card it looks like it would be fairly easy to get a Seaside server on the net, along with no monthly costs. It won't be a big corporate server with failover, backup, 24x7 support and chocolate unicorns but still, an easy and cheap Seaside Server. Got to be worth some effort, surely?
tim -- tim Rowledge; tim@rowledge.org; http://www.rowledge.org/tim "Bother!" said Pooh, as he pulled Piglet out the mincer.