I saw this post just after asking the same question ! But if the "Dual Hard Drive Kit" provided by iFixit is capable of...

For HTPC usage, the lack of a DVD drive in the Mac Mini Mid 2011 is a pain. Especially since you cannot presently find...

I posted a full tutorial in 2012 on 123macmini.com in, but this site is unfortunately dead. That post was titled Mac Mini 2011 w/ Internal Superdrive : SUCCESS !. I kept a save of this post and could possibly publish it again in iFixit, but reading your post and reading again (I forgot much ! :-) ) my original post, I am not sure it would help you any since I had no issue powering the drive once I fitted everything within the case. All my issues were mechanical. As mentioned above in my 27 nov. 2013 post, I used a Mac Mini mid-2011 motherboard board, not a Mac Mini end-2012 one. BTW, I am still using this modified Mac Mini for Home Theater :-) Update (01/17/2023): I re-posted my old 123Macmini.com post on iFixit into : https://www.ifixit.com/Device/Edit/Mac_M.... I must have done something wrong since the images I inserted did not display ?. May be somebody can help ? In the meanwhile, I can send my original post through email, and I did it. Hope this helps.