Context: I presently only have reasonable site access for approx 10-12hrs per day. (it takes me that long to write some of my posts

)
If my computer access was restricted to evenings (UK time) I would struggle to access the site at all. So for me, extra goodies aren't so much the issue, as being unable to cache already needed scripts from existing servers. It is only this site, it is always the same time period, it isn't client dependent, nor does it matter whether or not I'm logged in.
Not a moan, I'm a full grown fella and it isn't a 'real life' issue. So I work around it and enjoy the site regardless. The point, is that extra suites and additional goodies aren't necessarily a selling point to me. In fact as it stands, any goody that substantially increased server demand further, may actually have a negative impact on my experience, unless it's offset by additional resources..
If you want/need to introduce limited, well placed sponsorship slots, then I can work with that. As outlined in the OP it doesn't seem unreasonable.
If however, the principle was extended to the 'anything goes' philosophy, or Jafo's suggestion that a sponsorship slot every 10 skins in the gallery is acceptable, then were those slots filled, I would feel uneasy.
Not because of the impact on the site, all things being equal, as a site supporter, I'd cope with that if it was genuinely about sustainability. I'd struggle because the impact of the visible difference between sponsorship and adverts at that frequency, would have diminished to a degree where I would feel present subscriptions had been misrepresented.
I understand that's not the original stance and also the spirit in which Jafo made the statement. That said, as the position has been presented, it seemed reasonable to generate a different point of view.