It's possible that there are some out there of speakers with direct sound going through them, but I'm guessing they'd be really noisy. I made one of a stereo system speaker just to try it and the only use for it I've had is to add definition and some air to tracks.

My favorite IRs have been the Ownhammer ones that use solid state amps and aren't colored too much by the power amp. I don't think you'll find better IRs than that out there, even if you're looking to send synths or other sounds through them. That can sound pretty cool through most cabinet IRs too.