I think you're going to be hard pressed to find anything better than that price. Especially with unlimited concurrent connections.
My company (www.coresolutions.ca) does some filemaker hosting and we use a server at a rogers datacenter in Toronto but we've only just started hosting last year and so far it's only been a few clients that we've done development work for. I'm a developer so I don't know how much we charge but I doubt its below $20 a month although I suppose we would charge in canadian dollars so that's a 20% savings right there :P
Looking at our production server admin console right now I see we don't have any timeout set so it shouldn't kick you out if you just leave it open. Anyway if you're interested you can talk to Kris Hayward at 800.650.8882 x803 just don't mention my name I'm supposed to be doing real work right now instead of looking through forums... ;)
Great thanks! Sorry I should clarify, we don't need unlimited concurrent connections, I'm not being super cheap :) I'd be fine even paying the $12 per user. I meant we only have 2-3 users right now, so I'd rather pay a bit more or even similar but not have the unlimited concurrent users, since that's why there's the time out I think. I'll check out your site and see, thanks!