Bands that have never changed lineup?

The smartass in me wants to say Burzum, but there was that period where... Samoth, played bass in the band, during the Aske recording sessions?
 
Led Zeppelin, Strapping Young Lad (if you don't count the session musicians), Wintersun (No one cares about Oliver Folkin), Damageplan), Cavalera Conspiracy, Velvet Revolver, Stone Temple Pilots, The Jimi Hendrix Experience, The Doors, Steppenwolf
 
Tool's only had one lineup change since they formed. (Bassist in 1995)
Blind Guardian's only had one line up change since their first major release. (Drummer in 2005)
 
Led Zeppelin, Strapping Young Lad (if you don't count the session musicians), Wintersun (No one cares about Oliver Folkin), Damageplan), Cavalera Conspiracy, Velvet Revolver, Stone Temple Pilots, The Jimi Hendrix Experience, The Doors, Steppenwolf

Led Zep played several gigs with Jason, I'd consider that a lineup change personally, but that's subjective. The Doors have had 2 studio albums without Jim Morrison (so far) and also reunited in the early 00s with Ian Atsbury as their lead singer (though they have since changed their name to Riders On The Storm and gotten a new vocalist). Scott Weiland just quit Velvet Revolver. And I think they may have already done a gig without him, or else it's coming up soon.
 
Tool's only had one lineup change since they formed. (Bassist in 1995)
Blind Guardian's only had one line up change since their first major release. (Drummer in 2005)

Blind Guardian has had a session bassist for touring and albums since 1997. I'd consider that a lineup change since Hansi gave up bass duties to sing exclusively.
 

nah, there original bass player died. and they brought in another guitarist cuz kelly shaffer got horrible carpal tunnel

mastadon
ahab
belphegor (all the drummers are session drummers)
cephalic carnage (i think)
gojira
rush...? not sure
stevie ray vaughan and double trouble