Emacs is a great development environment. It just lacks a good text editor.

http://littlefe.net/, mentioned in the article, was the motivation for the Microwulf. LittleFeAR (http://www.littlefe.net/mediawiki/index.php/Main_ Page#LittleFeAR:_LittleFe_--_Advanced_Resources) has only three motherboards. But they're dual socket boards with 3.2GHz Dual-core Xeon's...12 cores total LittleFeAR use Infiniband/OpenFabrics with Mellanox Cards, so it uses a high-speed interconnect.

In other words, cost is the issue with microwulf, but other small-but-powerful clusters are also in development