You could use /whois ... It'll display like this:
Riamus is [email]Riamus@*EDIT*[/email] * Ria
Riamus has identified for this nick
Riamus on @#invision-beta !@+#Invision
Riamus using irc.irchighway.net The IRCHighWay Network
Riamus End of /WHOIS list.
As you can see, I am @ in #Invision-beta and !, @, + in #Invision. Since those are displayed in /whois, then you could write a script using the RAW for that to get the modes. I don't do a lot with RAWs, so I don't know which RAW this is right now. Someone else can probably tell you faster than I can find it out.
The only problem is that some servers/nickmodes prevent viewing the channel info of a user... although you USUALLY can view the info for any channel you're both connected to even if it blocks all other channels from being seen.
