If you have have a number of generic TLD's and they were syndicated for seed money to develop each 4 authoritative sites for the benefit of one new brand name: e.g. price comparison platform platform this would not be penalised as duplicated sites ?
Sounds a bit like black hat SEO, but I'll give it a stab. YRMV
If I read your question properly, you are saying that you want to create 4 sites that google won't think is spam - each of them promoting a brand name.
What will each of these sites contain? They have to have relevant content that readers would value - be it articles, games, forums.
Example: If the brand was coca cola, then one could creat 4 sites (coca cola racing news, origins of cola, coca cola commercials, coca cola sponsorships) and create [potentially] interesting content around them. there would be a minimum of cross linkings (racing news could be linked via sponsorships, commercials could refer to origins, origins could show historical references to the others). Each of the 4 sites also have to link build outside your network to really become authoritative.
That would be an acceptable way to split content amongst different sites and minimize the risk of being considered a link farm. One could potentially put each site on different hosting providers, each with a significantly different IP addresses / c's if worried about being penalized for being on a single host.
But - remember that anyone can (and typically will) send a complaint to google if they smell foul play. If you artificially raise your SERP in a competitive area, you can bet your competition will flag you.
I would say use your judgement. If it feels spammy then it probably is. If your micro sites add value to the end user then I would say this is a great marketing technique and in no way black hat. In fact, micro sites on specific niches are probably a good thing for the Internet.
There isn't any problem per se in using the same framework or back end, so long as the sites end up with lots of unique content that is genuinlly useful to the end user web surfer and relevant to the question they are trying to answer.
Be very careful about your quality standards - if your sites look too think or spammy and are interlinked back to your home page, you may start to look like a 'bad neighborhood' in Googles eyes and incur penalties. Build your stes and cross site links slowy and naturally and you will be fine.