Sounds like you want U3 compliance. I know it's been suggested before but I don't know if Khaled plans on implementing it. U3 compliance is better for your situation than mIRC in it's current form because right now mIRC still uses the registry, which means each time your Windows HDD crashes you're losing your registration info.
To be honest I haven't looked into U3 much and whether it'd require a separate version of mIRC or whatever, and this isn't really the thread to discuss it, but it seems like that would be an all-round better solution for the flash drive issue.
