I asked around and took a quick sweep on the net, which gave me this list:
Requires either a special client (available for windows and mac only) or use of a simple web api. There seems to be no ssh-based api.
OmniDrive currently provides a 1GB free account.
Same as with OmniDrive that it requires a special client to be downloaded and installed. Their client seems to have focus as a kind of backup application, in that it actually has features like backup in the background, and only transfer of modified blocks in files. In addition, you actually need to use mozyPro if you are a company.
Mozy currently provides a 2GB free account.
Now here is something in the lines of what I need. Their api is ssh-based, accepting sftp and rsync over ssh, which is just what I want. Aside from their apparent integration with basecamp, their focus seems to be providing a remote-disk, which is nice and simple.
Strongspace currently provides no free or trial account.
From what I can read, their focus is not as simple as strongspace, but I must admit that some of their features are cool. For instance, you can provide your email account information in their client, and xdrive will automatically strip off attachments from your emails and save them in your xdrive space. Real nice feature, but not at all what I need now :-)
Xdrive is an AOL service, so you need an AOL screen name. I cannot find any information about ssh-based uploads, so I assume it is not there. Hmmm.
They call it "Storage for the Internet". Sadly, they seem to only provide REST and SOAP based apis (which is fine, just not for me right now). In addition to this, they have a pricing model based on both per GB storage used and per GB data transferred in and out. I like a more flat rate price model.
So, I think I will go with strongspace, as it looks like a ... strong solution. Would like to hear from anyone with actual experience in this field though!?