I’ve been thinking this over a little bit. From a “business” perspective, the core of FW is sustainability. What it seems you’re suggesting is more along the lines of product diversity.
On the technical side, modularity seems like it fills both of these requirements. Wear parts and upgrade parts can be replaced easily without replacing the whole system. So far, FW seems to be committed to modular parts where there exist industry standard interfaces (memory/SSDs/wireless), and they plan to make some of “next years” parts swappable into prior chassis (so far mainboards, i18n keyboards, and expansion-cards), but they’ve been very hesitant to make promise beyond that (screen resolution/surface/interactivity, trackpoint mice, new expansion-cards).
Thinking about sustainability, I’m not sure that filling niche requests is the right way to go about this. (Not to say I don’t want niche products myself), niche items tend to be harder to produce. I think they’ll probably aim more towards the middle of the market with somewhat more mainstream products.
Perhaps if FW takes off as a platform we’ll see open-hardware and rapid-prototype/3d-printing communities pick up some of this. There’s another (short) thread about making an RPi Compute mainboard for FW, and I believe they’ve already released dimensions for expansion-cards and possibly other parts. I’d be surprised if the community came up with GPU hardware or anything major like that. but we’ll see.