I don't know if it'd work for you but I have all my defiant alts in one supergroup - this gives me the 20k prestige for each member (up to 15) plus the 20k prestige 'gift' for each member (up to the full 150, not that I have that many alts 
). That should easily be enough to cover you for an Oversight Centre and kitted-out Workshop. Of course it works best for me because Defiant is my villain server and Union is my Hero server, so I can get 12 in each group.
I can offer an alt to invite all your characters into your group if you'd like, but for the December 10th gift obviously I have the same idea as you and so all my alts are otherwise engaged 
@Hakeswell
Union Ilservian, Evinlea
Defiant Expeditor, Hakeswell
Arc: 70119 Hellion Initiation
Ok i have sent a Global Friend invite to you so we can discuss this in game. and thanks 
Actually, it doesnt matter. While looking through all my alts, i remembered one of my alts was made leader of a SG after everyone in it quit the game. So im just going to remove everyone from it, invite my main and other alts and just use it instead. The last member to be online was online 456 days ago -____-'
But just so u know im still able to use my own alts to fill up any SG rosters for whatever reason and thanks for the offer m8 ^_^
This sounds like an odd question, how do you invite your own alts into the SG? can you do it without a second person?
thanks
Eice
@Eiceman
Morphius - MA/Regen - Union
Taelan - Ice B/Ice M - Union
Hellyon - Ice A/SS - Defiant
Bubbletastic - FF/Energy B - Union
I am currently looking for some signatures to start my own "Personal" supergroup. however, the "supergroup" is soley to provide personal storage for my inspirations, enhancments, salvage, etc and i just need the signatures so i can get the bonus prestige so i can afford storage room. Everyone but myself will be removed from the SG.
In return i offer infamy. It would be best just to use Alts. If anyone else thinks personal storage is a good idea, i would be glad to use my own alts to help others obtain their own personal storage space
thanks for reading and i hope someone can help.