Santrex.net specializes in denial of service mitigation, offering reliable and secure shell hosting with rock solid DDOS protection. Their shell accounts are ran on a completely separate server from their regular web hosting, ensuring the utmost safety and stability for both.
I have heard that on any web host you are allowed to have shell access, but by the request, And santrex.net seems offers that without any request. That might be good for you. But to avoid any troubles I would recommend you discuss that shell accounts usage before signing up to make sure that evrything you are going to do is allowed on their servers.
As I see Santrex.net offers eggdrop shells, bnc shells, psybnc shells, bitchx shells, well mostly all irc hosting related legal packages. That's important for running shell accounts.