I like to poke my head outside of my own bubble and work on topics that I might not otherwise pick. I think that if you’re going to keep your mind flexible the best way is to solve a problem someone else gives you rather than one you decide needs solving. Over in this thread, Nerdvana asked:
If you are still looking for something to do, a group mind ability (as discussed in this thread or the likes of the Tines from Vernor Vinge’s A Fire Upon the Deep) would be intreguing. Basically a One Mind-Multiple Bodies issue. I had thought of Horde Intelligence but VickyM doesn’t believe that would do the trick.
That’s a interesting thought, how do you create a “one mind, multiple bodies” character? Well, Kromm came up with a useful method here. But that leaves the problem of the Ally/NPC angle. Basically, NPCs don’t pay points for Allies, Patrons, Contacts, etc. and PCs don’t pay points for PC allies either…or do they? Well, there are very specific cases where this rule simply does not apply and you might not even have noticed. This has been part of the design philosophy from Allie’s inception (so I’ve been told) and I’ve personally always treated it as such, but for those needing a reference see GURPS Zombies (p. 50). This is clearly a case where Special Abilities is turning Ally into a supernatural ability versus a social one. In the same way that NPC wizards can purchase NPC familiars with Allies, so can NPCs purchase a ability to share one mind among many bodies. Kromm’s method (and the best RAW model I think) boils down to:
Ally (individual of equal points; Constantly; Special Abilities, Can be played as PCs*, +50%) 
Mindlink (Allies) [varies]
Telesend (Racial†, -20%) 
* In effect, this Special Abilities enhancement lets you do what you like with the Allies, and is comparable to Minion, +50% in terms of waiving your obligations.
† “Racial” being used here as recommended for Duplication.
Yes, that’s expensive, a 60-point buy in is nothing to sneeze at, but it levels off a bit after that. Each additional body would add another 30 points and require that you spend 10-points on Mindlink. Now, that assumes that your bodies all possess the same number of points you do. This doesn’t always work for some builds because the “alpha-body” might possess superior capabilities, in such cases just lower the point costs. For example, if a super can force-link the minds of others and “slave them” to his own he might have his Allies worth only 25% of his total because they’re “just folks.” Similarly, you might consider amping up the telepathic abilities by adding Reliable, Broadcast, or Long-Range. Things get weirder when designing a race that’s got a single mind with multiple bodies because the vast majority of their points are going to go to their ability to have multiple bodies. It gets even stranger when you add in IQ mitigated by the number of bodies you have to begin with. Were I designing this I think I’d ignore the base cost for Allies and instead charge a cost equal to the Appearance + Enhancements, It wouldn’t be much cheaper, but it would decrease the cost some. I think this might also be a case where ignoring the usual rules for Group Allies might be appropriate. Perhaps create a entirely new enhancement:
Your allies are actually fully under your control and played as if they were PCs because you effectively share one mind between all bodies. This means that even if a body is killed, “you” are not because you’ve got at least another spare physical form. This does come with a drawback, however, if one of your bodies is becomes unconscious, make a Will roll, note your margin of failure as one of your other bodies also becoming unconscious for the duration. Additionally, use the rules for Ally Groups for over six bodies, despite the fact that each body might have its own personal traits. If your bodies are not susceptible to shared unconsciousness, add +25% to this value. This enhancement also assumes that you can eventually replace lost bodies, but the process is either costly, time-consuming, or requires a roll (pick two). If you only require one of these add +25%, if you require none of them – add +50%; if you require all three then reduce the value of Mindshare by -25%. This enhancement usually accompanies an appearance of Constantly, but this is not required.
Picking Over the Bones
Regardless of your method, this is a difficult ability to build properly and there are multiple ways you could approach it: Possession and Puppets, Duplication, Allies, Mind Control, etc. It becomes further muddied if you become more intelligent the more bodies you have, have a separate “mental body,” and so on. It’s probably best that you stat out your ability multiple ways to see which one will work best and then go from there. Even with other options I think Allies is the way to go because it makes a ton more sense than Duplication does and Possession or Mind Control would need to be heavily modified to work right. What sort of builds do you prefer? Any tips or tweaks? I’d like to know!