Luthier said it was working a long time ago so I think that politely asking for SLI support is within reason.
If you think having a SLI setup is 'wrong' or 'bad' here is why I have an SLI system.
I purchased a SLI capable MB because I enjoy triple screen gaming. FLight sims and racing sims are very nice with super wide fov and trackIR. I am not rich so I build my system a piece at a time.
I don't want to keep using softth (as great as it is) because I want a hardware solution (nVidia 2D surround is what I'm shooting for [
requires SLI] - just need 1 more monitor [or 3 new ones possibly

]). MatroxTH2GO had more limitations than just buying a 2nd card. As I understand it the super multimonitor nvidia cards are 2 GPUS in SLI mode on one card so I am not left with many options...
So there are valid reasons for SLI setups (even if you enjoy flight sims).
Cheers